What kind of camera equipment should I invest in next?

I own a Canon Rebel T1i along with its standard 18-55mm lens with image stabalizer, a quantaray 70-300mm LDO Macro, a Compact-Macro EF 50mm Lens, two tripods and an interchangeable reflector with 5 settings along with its holder. I am interested in hearing from other photographers what equipment I should invest in next. My job involves creating modeling portfolios, fashion and lifestyle photography. I think I would like to invest in lighting to make my models pop from the background, however, I am a college student and don't have much spare cash. A friend of mine suggested Alien Bees although I'm not sure what style of lighting I should choose. Any advice or recommendations would be greatly appreciated!