I really wouldnt split the room to veg, for that amount of space you could Easily get away with 1 mother in a smaller corner under a 250w HPS. If you had 2 mothers under a 250w you would have more clones than you could even use, then after you crop, butcher the mothers for clones and start 2 new mothers, a flowering cycle is more then enough time to grow some 2 foot mothers under a small 250w HPS.
Just close off a box in 1 corner and make it light tight for a mother area, anything more is a waste of valuable space.
You really should grab a dehumidifer if anything before buying new lights.
Also I would grab a 4 inch centrifugal fan and a fan controller, run the fan at like half speed so it will run silent, and it will be moving way more air than that little crapper fan can, then if you have the centrifugal fan you have the option of throwing a carbon filter on it when it starts to stank.
And check out cooling thermostats, you can grab a Control Wizard from most grow shops, real simple, you plug in your exhaust fan to the cooling thermometer, plug it in and set the temp, your fans will kick it when it gets too warm. And you really should get a little heater that you can set the temp on, that way its never getting too cold or too hot when your not around.