1-What is their purpose to my character. I do not seem to find any quests - other that bringing them sensors.

2-Problem - I went to Fort Independence and got the only qust to find tech, BUT problem is I tried to hack computer under the bridge to see what it was and now the Brotherhood Outcasts attack me. I had to get rid of Outcasts guards to escape. Now they attack me allover. Is there anyway to get back into their fold besides going way back to an earlier save???

Might be able to use the console to alter your rating with the outcast faction. I don't know what that command would be atm but I'm confident you'll find the answer with a little searching or some kind member here will know how to do that.

well at leats thanks for the tip on what happens with that computer

should always save before something something like that =]

Spoiler - Yea, the computer under the bridge is for turning off the Bridge Machine Gun Turret.
I did go back to an earlier save and went back to Fort, but found The Brotherthood Main character was just being blown up by Raiders. I guess xbox360 version went bonkers!! There were about 14 Raiders attacking from all over and just ran out and hid untill it was over and they left. I then went out and picked up all the Motor powered equipment from the dead Brotherhood Outcasts. I still have not figured out how to get trained in using the Power Hardware. The Citidel still does not let me in!! Yea, the PC version I'm told you can just type it in but I on the 360.
OK- Thanks.

Follow the MQ. You get in not long after you find your dad.