Openings

Hello! - Has anyone got any advice on how many openings should be part of my repertoire?

As only rated 1100,i was thinking I should keep it small?, for example as White I always try begin the Itaian Game.. and take it from there..

As black I often get caught out which defense to play, especially when D4 not E4 is played!.. ive kind of learnt the Najdorf variantion of sicillian, but is that too advanced to be considering for my rating?

I like open games more than closed ones! - ive even looked at the kings gambit but didn't have great success!...

Im kind of hoping someone may be able to suggest a list of 3/4 opening main lines I should learn... ?? Anyone!?

I'm currently working through tactics books, and also an endgame study, Im really conscious of my weakness in the opening!... Help!!!? 

 The Nimzo-Indian Defense has worked well for me against 1. d4. Black eventually tries to get in c5 to equalize in the center after quickly developing his kingside & castling.

Thank you Kemp7, ill give it a look..