First you might want to read up a little bit on light diffusers to see what kind of diffuser/lamp might work for your office. Then you can go just about anywhere that sells office lighting products, either in person or online and simply describe the situation (including your budget).
You might want to check out UltraLux
GE Lighting
Here’s a very attractive diffused office light fixture from Stardust Modern and it’s only $60.
Here’s another nice looking light fixture from Lighting Universe for $78. It’s made by Lithonia Lighting model 11692RE.
Here is a selection of LED office light fixtures that might be better than fluorescent lighting with regards to bulb life.
And here is a standard indirect fluorescent fixture from the same company as the LED’s.
Finelite makes some good looking commercial products.
Or Phi lighting
Good luck!