I'd try taking some shots during daylight to begin with, it's a lot harder in low light. For example, the second photo of your mate has come out blurred due to a long exposure being needed. You can get some cool effects with long eposures (see the motorway bridge thread), but without a tripod chances are the images won't come out well. As a tip if you don't have a tripod I'd try resting it on a wall or similar.
Also, the picture of your car is underexposed as the flash has highlighted the reflective numberplate and has cast everything else into darkness to compensate. If you can I'd take it off auto and put it on to Shutter priority or even Program mode and choose a longer exposure, with no flash and a fairly high ISO; that should bring out more detail in the rest of the car.
In general the white balance is a bit too orangey for me, but that's easily adjusted, either using an pre-defined setting, or setting the custom white balance by taking a photo of a white piece of paper or something.
The fourth shot has most potential for me, I'd just keep going and experimenting and you'll learn so much. Hope I've said some things that will help you anyway dude.
In terms of lenses, if you want to buy new try:
www.camerapricebuster.co.uk, or
www.jessops.com
www.jacobsdigital.co.uk
www.amazon.co.uk etc etc
Ian
