Catapult has too many faces

Got bored earlier and decided to go ahead and make a very simple catapult with a fiery ball as it’s ammo! I’m relatively happy with how it looks but the problem is that it lags a lot with the amount of faces. Can anyone look at the Blend file and tell me were i should be cutting down.
If you could also tell me how to make improvements that would be great :3!
http://www.mediafire.com/download/ijjjf0c78qyw497/Catapult.zip

^ Blend file


I’m working on it. In edit mode, there are flat places filled in with a ton of small faces. I’m joining them into a single face to reduce the face count while not affecting the appearence,

And the front right wheel looks a little buggy in rendered view

EDIT:fixed

What you need to do is, find a grid of faces in edit mode, select all except the outer 2 faces or so, delete them, alt-select the outer loop in line select mode, then fill it (F). I think it WILL mess up the UV but it shouldn’t be that hard to fix.

Don’t delete them, dissolve them. Should retain the UVs.