You'll want to keep in mind that there are several different factors which make a credit score and these include longevity of open accounts, types of accounts and credit limits.
First of all you need to consider how much your limits are in relation to how much you owe on your card. You said that you have a combined limit of $800 between two cards? Are they both maxed out? If so this is very detrimental to your credit score. Paying down your balances if this is the case would be the most beneficial thing that you can do. A quicker solution to this would be to call your credit card companies and ask them to raise your limits. You want to keep the percentage of your debt to your credit limits at a maximum of around 25-40% to insure a high score. For example if you owe $350 on one card with a limit of $400 it would raise your score to pay this card down to $100 or get your card company to raise your limits to $1,400. This would succeed in getting you at the 25% mark.
At this point to answer your question with what I know I would say it would be best to stop using your cards and to continue to pay them down as much as you can each month. Also make sure that you are making ALL of your payments on EVERYTHING on time, if not a few days early. This should help to bring your credit score up. For more information you might check out my finance blog which covers this topic at: http://debitversuscredit.com/2007/10/how-your-credit-score-defines-you/