1. Yes, your bank should have a record of the IP address on its server.
2. By using that IP address you should be able to find out which ISP that person is using.
3. ISP can locate IP by using NetMap. Then they can find out more details by using authentication logs (username, or RAN / Nas Port).
4. If that person is using a static ip address, it will be much easier, most ISPs assign it to the phone line.
**But the bad new is, ISP will only give those information to police, not even your bank, if you really want to find out, you need to log a policy report, or ask your bank to do it for you.
My suggestion is, first change your login ID and online passward, then leave your modem off about 5 to 10 mins, ( you will be assigned another IP address, you can check your IP address on www.whatismyip.com). Most importantly, be more carful when using online banking, check your computer as well.