Yes, it is better to beat someone with a higher rating.
The ratings of your opponent and yourself lead to a certain "expected score"; let's say that you should beat a 1100 90% of the time, and a 1700 should beat you 90% of the time, so you are expected to score 10% (not the actual numbers).
Then the rating change is related to the actual score compared to the expected score; if you beat the 1100, you do 10% better than expected, and you earn 10% of some amount, if you beat the 1700, you do 90% better than expected, and you earn 90% of some amount. Same for drawing (50%), and losing (0%).
This is very simplistic. The amount is also adjusted for how reliable the ratings of you and your opponent already are (the less reliable yours is, the more wildly it can vary... it settles down over time).
There's much more explanation in the "Chess Rating system" sticky in the general chess section.
I dont know which is the measure in order to win ELO points... now i have 1424 but i dont know if it is better to beat a member with more points than me... do i receive more points for this? or is it equal to beat another member with my same points or less? Can anyone explain this to me... Thanks.