Wanting to change the background on Gallery 2.3

Hello everybody, I am hoping someone can help me out here. I am new to this software and want to spice it up a bit. I am starting a Radio Control club and wanted to put some software on my site so the members could upload pictures of their models and such. I came across Gallery 2 and really liked the way it worked but it is a little plain and would like to tweak it out a bit. For one I would like to put a nice background on it instead of the plain white background. I would also like to remove the links on the bottom and increase the site of the logo box on top.

I have been reading and reading on this site and I am a little nervous about editing files that may crash the entire software and would like maybe someone that is willing to help and maybe make a few bucks to help me get this the way I want. But any help would be great...

Sincerely,
JD

Site: http://www.aggielandrc.com/gallery2/main.php