That's interesting, do they allow that change into the estimated living costs?
First off, I just want to say dpmd has great advice, and that's the place to start. But yes, many programs will allow you to apply for a budget increase. At my school they allow an increase to cover car payments, car loans, car insurance, parking (other than school parking), moving costs, furniture, healthcare bills. There might be a few others they allow, but that's all I can think of.
As DrMidlife points out, credit card debt is not something you can get additional funds for, so you would have to justify the extra money you need another way. That's what our financial aid offer tells us--I got married but you can't get money for a wedding/honeymoon (FYI it was a budget wedding) but my financial aid officer worked with me to find things I could get money for so that I had enough to cover the wedding costs.
I've applied for budget increases at my school and they've always worked with me and approved things that are approvable. At least at my school the extra aid comes in the form of school-certified private loans, but I've heard of other schools that are able to get federal loans for their students (which would be far preferable, though my private loans are all at 2-4%, granted they're variable rates)
There's great variability between financial aid departments and how much they'll help you. My medical school has it's own financial aid department at the school, so we don't have to talk with the undergrad financial aid people.
You first step if you're even thinking about applying for more loans is to talk to your financial aid officer to see if it's possible at your school. But even if you do take out more loans, absolutely do whatever you can to reduce your costs wherever you can. You don't want to skimp on things that might be needed (some schools really require a car in the clinical years--but you can probably get by without one for the first two years), but if you can find good people to share an apartment (and potentially a room) with, then move in with them.
I found the following blog has some really helpful posts on saving money:
http://www.mrmoneymustache.com/
Another quick/easy way to save money is to ditch the smartphone if you have one and are paying for your own plan. You really don't need one in medical school. I didn't, as well as one of my friends. And older ipod touch or pocketbooks do everything you need. Computers located throughout the hospital do the rest. Or, if your contract is over, look at the post above and you can get a basic bare-bones plan for as low as $10. (that one won't work for most people, but they and the other companies have more affordable plans than the main wireless companies, and they use the same network).
Anyway, I had a number of friends who didn't even take the full cost of attendance--if you live like them, then just borrow the full cost your first and maybe second year so you can pay off the consumer debt asap. Really, try as much as possible to borrow as little as possible. You don't know where the future of healthcare is going and the odds are loan forgiveness won't be around for us to benefit from (it may, but it'd be foolish to count on it), and if you do have to get private loans those don't have the benefits of federal loans (though they can be deferred in residency). Still, the rates can go way up on those private loans...
I hope that helps a bit.