Neil McKenzie
It's tough - but keep on going and it will get easier. You should also learn some minor chords: Em, Am, Dm are the easy open ones. The chords you have learned are all major chords and most songs need a mixture of minor and major. Once you add some minor chords, you might find things sound a little better.

Wayne T
Find a teacher.

jhawk
I am a guitar teacher. Really, what it takes is practice. It can definitely be frustrating, though. As a beginner, try to start with simple songs and melodies--if a song is too difficult, you'll get discouraged easily. Come back to those songs later when you've improved some. Also, alternate between practicing chords and playing single note melodies--this will keep things more interesting. Play music you're interested in. If you can find someone who plays the guitar, they can give you some tips on the correct and easiest fingering of the chords--sometimes this can be a hangup. Good luck and don't give up!

Tony B
If you want to quit after learning 3 chords maybe you should? There really is no point in learning an instrument if you expect to be able to "do it" straight away and if you don't enjoy learning. You'd be better off spending your time on something you enjoy - life really is too short!