Make sure your proportion of credit used to available credit stays low, and don't apply for any credit that you're not really sure you'll get (but do seek additional credit), make all your payments on time, give it a year and your score will improve. You can get a car loan now (don't be shocked if it's a 12%-16% rate, and go for the lower rate by making more down payment), and refi in a year. If you haven't joined a credit union yet, do it yesterday. Sometimes having a relative in a credit union when you don't necessarily qualify to join one will get you in.
I used to pay cash for everything when I was younger, and only had an Amex and Mobil gas card as a credit history and had to really get to know the credit system to build a history correctly. In your case, paying a credit repair service the $500-$1000 fee would be worth it. They can write letters on your behalf, and get you back on track with much more ease than you could do yourself.
JV