Discover card interest rate change

Hello all... I'm new to this site and have been reading as many posts as possible trying to educate myself on your credit wisdom...I'm very impressed with what I see! I've been keeping myself in the dark on my finances and I've decided it's time to turn the light on. I do have a couple of issues that I'll be posting soon that I need advice on, but I'll start with my Discover account.

Some background...I've had an account with Discover since 99. In 2001, (I believe) I made the mistake of letting a family member use my account under the guise they'd make all payments and pay the card off... well, they didn't. I'm not sure how many payments they missed, but the interest rate jumped from about 8% to 14.99%. I figured out what was going on and resumed making payments on now the $5000 balance. (My own charges on the account add up to $2000.) I understand what a mistake this was to let someone else charge on my account and I'm taking full responsibility for all charges...

Now in March 2003, I had a late payment (I just neglected to mail it in ontime) and got it credited the next month...they tried to raise my interest rate but I caught it the next month and they credited me the finance charges and the late fee.

Then in May I was charged another late fee... but this time it was because of their website messing up and when I tried to call the CSR she said their system was down and that I wouldn't be penalized if I made the payment later.

Well I was!.... my interest rate went up to 24.99%

I know this was something I should have taken care of right away, but I didn't. I am going to call and try to get the interest rate adjusted... but do you think I have any chance getting back all the money I've accumulated from the high interest rate (probably close to $800) or should I try to do a little credit repair on get a card to do a BT. (My scores are in the low 600's.)

Sorry for such a long story... I wanted to give all the info. I'm excited to start repairing the damage I've done by just turning a blind eye to my finances and credit.

Thank you for your help.