Hi Steven, you've already received a lot of good advice to help you short term. I want to address your question in the long term point of view so that you never have to be in this situation again.
1. Your credit file must be built thoughtfully, carefully and strategically, account by account. Make sure that you establish a good mix of credit via both installment and revolving loans, credit variance accounts for 10% of your credit score.
2. Do not close old inactive accounts, keep them open and keep them active so that the issuers do not close them. The older your accounts, the better. Length of history accounts for 15% of your credit score.
3. Keep your balances low in relation to your credit limits. A good rule of thumb is to keep your balances under 20% of your credit limits. Example: If you have a credit card with a $1,000 limit, keep your balance at $200 or less. Amounts Owed accounts for 30% of your credit score.
4. Limit yourself to applying for a maximum of one credit transaction every 6 months. New accounts will lower your average length of history and too many hard inquiries will tell creditors that you are hungry for credit and lower your credit scores.
You can read a little more here: http://www.creditfirm.net/blogs/change-your-thinking-about-c