Type's of hood's make a big diff with how the light is directed. If you want the light more focused, a batwing will do the trick. If you want it more spread out get a parabolic. these are both open type reflectors. As long as your circulation is good it won't be prob having an open bulb, especially if it's in a basement. I have a 600w hps along with a 430 in a medium sized bedroom in the basement and the temps never go above 25 with only a 195 cmf exaust and a household fan blowing air into the room.
He's right, hoods can/do make a big difference, and there a number of variable reflectors that you can get depending on your specific application. However, I would clarify that parabolic reflectors aren't something that you want to use in your situation flowering w/ only one or two lights. The light is spread out so much that it decreases the lumen efficiency significantly, but it is applicable in the vegetative room.
An A-wing supposedly delivers the most light (and usually economical), while the SunSys (US made), Bell Light(Canada made), Hydrofarm are all examples of brand name hoods that are good horizontal, typically w/ the option to air vent, reflectors. There are many more that are sufficient, it just depends on the size of 'blueprint' that you want. Btw, I would recommend Hortilux bulbs, if that isn't what you already use. Typically higher lumen output.
Depending on where you live, I would start by checking out plantlightinghydroponics.com. If they don't have what you want move on, but they have some of the best prices on the web. Dchydro.com is decent, but website sucks, there are a couple more just Google it.
here is a quick article outlining options:
http://www.planetnatural.com/site/xdpy/kb/grow-light-reflectors.html
heres a quick vid from high ass 'big mike' from AN (not a fan, but decent, quick breakdown):
http://www.youtube.com/watch?v=ExAucI_B9d0
Hope this helps. Good luck!