Hit by a car bent rim I have a new 199.99 Schwinn I got from Wal-Mart a few months ago.

Just the other day, a lady didn't stop for me and knocked me off my bike. The front wheel was stuck under her SUV, rest of the bike is fine. Now, it's still rideable but has a bent rim that wobbles when I ride.

Is there a way to repair by straightening it rather then replacing it?
It depends on how much the rim is bent, and if the deformation is lateral (side-to-side) or radial (in the direction of the spokes).

Take the wheel to a bike repair shop and get it evaluated. The shop may be able to true it. If it's not repairable they should be able to recommend a replacement.

As a safety precaution, don't ride the bike in the meantime.