I've been playing guitar for around 6-7 months now, and I write my own stuff.
People tell me i'm pretty decent.
But the only problem is i have around 3 songs with the same strumming pattern. And now, it seems like that's the one I come back to.
How can I get some more strumming pattern ideas? And how can I quit this one? :P

help is appreciated.
best way to obtain new technique is to think outside the box. for strumming patterns, i'd say the most effective thing to do is develop your repertoire further. not saying you suck (or anything of the sort), but if you're playing guitar for only 6-7 months then there's likely a lot that you can still do to develop some innovation. learn more songs.

i recommend allan holdsworth stuff. but then again, so does everybody.
Put your guitar down, decide what rhythm you want (tap it out or somthing), work out what the strumming pattern for that rhythm would be, then pick your guitar up and, starting slowly, teach yourself how to play it.
You could pick up some ideas from listening to music, the process zhilla describes above. I'm sure you could find a lot of strumming ideas online if you do a search for "rhythm patterns" or "strumming patterns."

If you are looking for a book, there's one called "Rhythm Guitar Encyclopedia" by Jody Fisher that basically has over 400 rhythm patterns in it in many different styles such as rock, blues, samba, funk, etc.