You need to use different textures. It's be next to impossible to make a nice looking using the standard textures. Try finging some online. I'd try screwing around with 3DGS before you dive into a game. You dont have to listen to me though, I never did when I started. But I never finished anything either.
Well good luck anyway, it sounds like good concept.

@ lostclimate: It's a laboratory so why to build it like a Hilton hotel?? But I think you are right. I'm also not content with it, I'll work on it...

@Metal_Trasher: I was looking on the internet yesterday and I found some very good looking free textures. I modified them a bit and build them in. It looks better now...

what it needs is more along the lines of thin rails, lots of pipes and wires
metal plates, steel racks and tabels with generators everywere. have a look:

http://www.slipperybrick.com/wp-content/uploads/2007/01/stargate-atlantis-railgun.jpg
http://www.kek.jp/photoarchive/accel/ps08M.jpg

obviously you wont have a turret there, but look at the rest of the environtment, and look at the walls and look at all the little things you might have overlooked before. it really helps to find some good reference pictures when you doing level design or modeling.