Lens advice please.

[cartart]

Hello All. I need some advice on camera lenses please. I have a Sony a200 (55mm lens) at the moment. I need to take some marketing level/website quality shots of our recent office refurb projects to put into our updated advertising. I only have the kit lens that comes with the body but I do have the powerful big Sony flash and a tripod and a remote activator.

I need a pointer as to the right type of wide angle lens to help me get better pictures of broader views of the subjects - can you help?

Thanks in advance.