Im about to start growing in my attic (its small, about 3-4ft high and 3ft wide, and like 7ft long.

Im buying a lamp but i dont know what to get. Im gonna grow like 3 plants at a time (or more if you think I can).

At the moment im leaning towards going and buying a purple fluerescent light from a gardening store, and a fluero bulb to plug into a normal Australian fitting thats like 1ft away.

But what do you think I should do and what are you comments on my planned set up?

And what about reflecting? Will simple white cardboard poster sheets do? Tin foil? Alum foil?

Oh, and where do I get any lights that you're mentioning. I can go to a hydroponics store and get lighting from there if i have to, but its on the expensive side.

Your attic grow is actually a fairly difficult proposition to pull off, here are a few things to consider:
(1) lights, you will need at least a 600w sodium halide to do an effective garden, and by the specs on your attic, it would have to track back and forth, unless you just want to grow the 3 plants. You can buy 250 w self ballasted fluorescent for about $100, this will grow plants, but they will be long and loose, your yield will be enough for personal smoke, and not much else.
(2) growing medium, just buy potting soil, big bags at home and garden, put your seedlings/clones in the pots, fertilize with 10-10-10 once every 2 days, dissolve it in water first.
(3) light cycles, 24hrs until they reach 1.5 ft height, then 12 on 12 off
(4) budding, as much fresh, cool air as possible. Harvest when the buds are dense and sticky, they look way smaller when dried.

Yeah, a fluorescant wont do it. Hell, when I grew my 'furns' in just enough space for them to fit, I had nearly 200w of fluroescant lighting and it was a fuckign waste!

First off, I wouldnt use the whole attic. Ide use a small portion of it to set a scrog box in. A scrog box basically allows you to grow the plants in the most minimal amount of space [say 30 inches high, and a width and depth just big enough to fit the medium] therefore utilizing your lighting as best as possible. As well if you use the whole attic you'll have a bitch of a time venting out smell's, whereas with the scrog box you'll be able to use a store bought exhaust fan, plus a carbon scrubber to eliminate just about all odors. And dont woryr constructing a caron scrubber is cheap and easy.

With this you can save on expensive HPS lights, as you wont need such a high wattage one. [you need 50w per square foot] I first suggest you goto www.overgorw.com and check out the forums and faq for info on genereal growing [like mediums] and specifically scrog. As well theres many links for lighjt dealers on there. I know of a really good one, but shit, I cant remember, but I know its floating aorund the overgorw forums!