You may have trouble with vinyl, leather, or anything heavier than tweed with a non-walking foot machine. I'm not saying this to discourage you, but a decent walking foot machine can save a lot of tears and headache.
For a 1 time project, see how far you can get with the singer. If you plan on doing a lot of interior work or several cars, I would consider getting a low-end industrial machine like the consew 206-RB5 or perhaps even a Juki if you wallet will allow. You can get a Consew with table and motor for around $1,000.