Your plant is so streched out probally because the lighting your using . You say your using a 100watt light bulb so im suspecting it is just a plain jane house incadecent, and im also suspecting the 150watt is one of those crappy incadecent grow bulbs. Your plants are strechy because the lighting isnt at the right spectrum (kelvins) and your plants are streching to try and seek out better sources of light. You need to upgrade your lighting.

You can get a 2-pack of 26 watt CFL (compact florecent) bulbs at walmart for like $6.50 Get bulbs that are in the 6500k range (walmarts "GE brand" 6500k Cfl bulbs say "daylight" on the package) , a extension cord for like $1.50 , and a 2 way socket adapter for like $1.50 , and you can get to socket plugs for about $1.25 each (a socket plug is basically a light socket that you can plug into a wall outlet).All of that is availible in the lighting section of walmart. Like $12 bucks total that should allow you to vegg the plant well.

As for Hps bulbs your going to need a ballast they dont work in normal light sockets , if you choose to use one. And you plant looks indica dominant to me.