Lens and settings for nightclub type shots

karenmay700

I recently purchased the T2i and I'm very new to the photography world. I would like to know what type of lens you would suggest and what settings are best for getting shots in nightclub type settings.
My husband is a DJ and we've always struggled with getting a good shot of the lighting and people. We either get a great light shot with blurry people and/or end up with lots of grain. He also uses fog at times as well. Do you have any pointers?
I know I probably will have to purchase another lens for this. Which would you recommend on a budget?
I currently have the Canon EF-S 18-55mm and just bought the Tamron 75-300mm lens.