Im using a 250w infared heat reflector buld. Is the a good decision as a light??

For growing marijuana no. Big waste of energy and puts out a lot ot heat.

What Wattage should be used, and how many lights should obtain to grow a strong plant??

You can get a 300 watt security light at walmart for about 10 bucks. That will get you through a couple weeks after that you are going to prolly want to switch to something like this Home depot light bulbs at least or at best 1000w HPS with a nice ballast for indoor growing.

thats a very vague and indescript question. its not the wattage that matters, its the bulb type. a 42w compact fluoro will put out a shitload more light (in lumens) than your 250w heat lamp. when growing cannabis, the more watts the better, to an extent. a 1000 watt HPS/MH bulb is useless if you cant evacuate the heat it radiates. so it really depends on your fiscal and growing space situation.

so I can use a 42w compact fluoro and get good buds?
what is the cheapest way to go?

u couldnt even use one 42 watt cfl to grow one plant

What the fuck are you talking about? That one 42 watt cfl could grow 2 plants with the right reflector and various pruning techs. I have seen it done with alot less than that!