can i still help the NCR prevail if i work with Mr. House or should i just take over New Vegas and use the robots to help the NCR?

If you side with Mr. House, though, you won't be able to ally with the NCR or Caeser's Legion. And if by "take over New Vegas" you mean help Yes Man, you can't help the NCR if you do that, either. Basically, there are four end-game factions:

NCR
Caeser's Legion
Mr. House
Yes Man

Choose one.

ah i see thanks