First off I doubt you'll be pulling more power for a grow than you would be for a well used washer and dryer combo so don't worry about power. As for fly overs with IR there isn't much you can do about the light but the room's only going to be 23degC anyway.. a dryer gets hotter than that.
Attach some hardboard to the rear of the louvre doors to light proof them. Get some no-more-gaps and run it around all the corners to airproof the room. Install an interior wall that divides the room vertically, from floor to ceiling. Ensure that light from one side does not affect the other.
One side is for 'vegatitive' growth - should be big enough for a mother and 6-10 clones (15"x30"?). Get yourself a couple of flouro bulbs that's all you'll need in there for light. (the little energy saver ones) Try to set it up so you can get into this room without disturbing any plants in the flower room that may be sleeping. Cover the whole room with white mylar (panda film) it reflects the light, it is easily cleaned and (renting?) will keep mould off the landlords cheap MDF cabinetry. You want to ensure the floor is protected from water damage so you get your bond back.
The other side is for 'flowering' you want it bigger - that's the fun side. That's where the big light goes, with HPS lighting you want roughly 50w
per square foot of grow space so 450w - 600w HPS should be sweet. Keep the ballast away from the plants.
Both sides need ventilation. You need the hot air coming off the light to be sucked out of the room quick - your exhaust is placed up high. You want clean air coming into the room and blowing on the stalks of your plants to toughen em up a bit, place the intake fans low.
Ducting.. not enough details provided to help you out there - where do you want the stinky air to blow? Out a very high window means it will dissapate before reaching nose level. Just be subtle. Carbon filters kick ass.. maybe save your dough for one of those. Get some sealing tape, the fat spongy stuff you use to block draughts around doors and windows, and run it around the doors to help smell proof the unit.
Where is the power? If it's inside the unit you've got a lot of electrics running beside water, if it's outside you have a lot of plugs and timers to explain.. work it out.
Lights and filter aside you could probably set up everything I've mentioned for 2-300 dollars. Draw up some plans before you start with tools. Then erase them and draw better ones... figure out whether you wanna do a SOG or a SCROG and what media you wanna use.
You'll be fine, just take your time and keep it simple bro.
Watch this movie too..
Grow DVD - Top Quality Marijuana Growing.