looking good! it's gunna get stinky. just get some gel air fresheners, try to get fruity smelling ones, like cherry. burn candles in your house. you say your limited on funds, but ona gel would take care of that lil room no problem. those are the cheapest ways to cut it down. an activated carbon filter would be best but even the 4" combo's are gunna run ya $100 plus shipping your fine using cfl's on autoflowers, if anything just get a couple more, but get the 63 watters (300watt equal) there $15. mount them horizontal.
if you do get the 250, which imo is not a good idea unless you have a 3x3 box with ventilation to outside the small room. that room is directly under a roof and in the summer you will have a lot of heat issues
how many hours do you want to run your lights if you have a 250 hps, and how much do you get charged per killawatt hour? also a 250 watt hps/mh uses 275 watts
to figure it out this is the formula:
hours x watts divided by 1000 x cost per kwh x number of days running
i would run my lights 20 hours, and right now where i live it's $0.11 per kwh
20 hours x 275 watts = 5500 divided by 1000 = 5.5 x $0.11 per kwh = 0.605 x 30 days = $18.15 to run your lights 20 hours a day for 30 days at $0.11 per kwh.
here's some at $0.12 per kwh.
12 hours for 30 days = $11.88
14 hours for 30 days = $13.86
16 hours for 30 days = $15.84
18 hours for 30 days = $17.82