As others have said there is something more behind this. All the punishing in the world won't fix it.
If all your punishments, including police, have had little effect so far then you have to consider that your daughter might be addicted to something that she has to have money for. Alcohol, cigarettes, slot machines, pills, the buzz of buying things for her friends... It could be anything. Really talk to her and importantly listen. If that gets no where ask the school if they have a counceller she might be able to talk to. Sometimes it's easier to open up to a stranger when you don't have to deal with their disappointemnt in you.
Do not give her your bank card ever again and make sure you get the pin changed. She has shown she can't be trusted with money and has a problem, so don't be putting temptation in her way and then wonder why she takes advantage of it. Don't leave your purse or money lying around where she can get to it. You have a responsibility to ensure she can't be tempted to steal while you sort this out.
I myself stole money from my mother's purse. It all started when i needed subs money for guides. I found it very difficult to talk to me parents and even now still have trouble asking for things. So rather than dealing with asking, and being hurt by saying out loud the equivalent of 'you have no interest in my life and aren't even aware that i need to pay subs for guides or whatever it might be and that really hurts me' I just took the money.
On some level too I now think I was angry with my parents too for not caring enough to know these things and not knowing that i needed money for subs and the other things i took the money to pay for, but mostly it hurt that they had no idea about my life and i didn't want to draw attention to that to make it even more painful. I didn't have a very happy childhood and my parents were too busy and much older so didn't have time for their children.
I had (still have) no idea how to talk to my parents or that i could ask for things. I then started taking more and more money so I could buy sweets on the way to school like everyone else did, and to suppliment my lunch money which didn't cover the cost of lunch in the cafeteria but I couldn't tell them that. And then I treated a friend to her sweets, after which she expected me to buy them for her all the time as she had no money and i had rich parents in her eyes. I didn't have many friends so thought I needed to do this to make sure she stayed my friend.
It finally came to a head and my Dad spoke to me about it, though he never asked me why i took it, but said that they would start giving me some pocket money in future. It was a real relief in a lot of ways to be able to stop. I also got myself a weekend and holiday job at the age of 14 so I earnt my own money at that point.
You really need to teach your daughter the value of money. She simply doesn't understand about your budget. My son certainly doesn't understand when i say we have no money for the cinema, but i then go and put petrol in the car and buy food or we go to the play centre because i have money left in those budgets but not in the school holiday budget. Your daughter is old enough for you to explain these things to her.
Talk to her about how much money you get each week and what you have to spend it on. Show her what is left after bills and how much you have to spend on food, clothes etc from that. Then take off the extras you do for them etc.
Your daughter probably doesn't see the money you spend on her school dinners, karate and guides as money you give her. Your her mum, it's your responsibility to provide these things in her eyes, she doesn't think of it as money you give to her. Show her in your budget that you put aside so much for her activities and what you actually spend on her out of all your money. Make it clear this is money you regard as spending on her personally and that you choose to do this, you do not have to do it.
£5 a weekpocket money is a lot I feel, but if her dad wants to give that to her let him. Insist she pays you back what she owes from that money, at say £1 a week and also by getting a paper round or other job (washing neighbours cars, walking their dogs etc). Tell her sister not to lend her any more money and that she is to ask you before she gives her money in future.
Get your daughter to set up her own budget. So of her £5 pocket money £1 goes to you to pay back her debts, then £2 on magazines, £1 make up, 50p sweets, 50p savings. Get her to budget out what she spends and show her that if she wants to buy something specific she either has to save up for it or cut back on her other budgets to cover it. Teach her the value of money now or she will have a problem when she is older.
But most importantly try and get to the bottom of what all this is really about. My parents never did that with me, and i still have a problem today with asking for things and with spending money on myself.
Best of luck
Gilly