It ain't gonna get better by sitting here complaining about how bad you can do you powerchords.
The essence is all about practising my friend, practise, practise, practise. I too had it difficult to learn powerchords. There are two ways to perform a powerchord.
e|---
b|--- This is the first way. You place your INDEXfinger
g|--- before the 2nd fret. Now, let's place the RING
d|-4- finger before the 4th fret and place your pinky
a|-4- on the d-snare before the 4th fret. It takes a while
e|-2- to get hold on, but when you have it it'll only smooten.
Or another way to do is (the way I do it) is to take your INDEXfinger and place it before the 2nd fret. now take your RINGfinger and 'barré' the 4th fret on both snares !
It won't come easy, like I said, your fingers wil need a time to adapt and get used to the little stretch. Pick the way that's most suitable for you, but I suggest you'd learn the first method because when you progress you might find it handier when you have your pinky allready 'standing by'.
Hope it helped, just keep practising and I ope my explenation made some sense :)
Latz, Gulder