Wow, nice thread! I thought I was in the C & V for a bit.
The logical answer to "Vintage or New?" is both. When you can afford them, of course.
An older bike that you can fix up yourself is the better buy, especially with your budget. CL and garage sales are your best bet, just be patient. Make sure you know what size bike will fit you.
Sheldonbrown.com is a great place to learn lots of stuff. Here, the Classic and Vintage forum and the Mechanics forum are also good places for info.
Sheldon's Beginners section