With a reflector like that it will be capable of putting more lumens towards your plants then just a bare 36w CFL, but the question becomes what is the degrees Kelvin of the bulb?

If your vegging then you want 5500K-6500K, if you're flowering then you'd want 2700K-3000K.

As dustoxx420 points out, CFL bulbs can be had relatively cheap, maybe just more bulbs are your answer. I'd look for a deal on a six pack of bulbs.