So I'm living my life enjoying my fantastic macbook... first day I bring it home I open it up, bang it automatically connects to my home wireless internet i didn't have to look at any settings etc (so i don't know what the correct settings actually look like

So i have a peek at the network settings and i get
Airport status: On
Airport has the self assigned ip address 169.254.xxx.xx and will not be able to connect to the internet.
Which i can't. Which sucks.
The airport thingy up the top is faint with an exclamation mark over it... I have a tick next to my home wireless network so like im connected or whatever but it also says Alert: No Internet Connection.
I have other devices connected fine to my wireless network and accessing the internet so im pretty sure its just some settings on my macbook got messed up or whatever, if anyone could help me out i'd really appreciate it!
I tried all the old tricks of resetting the wireless network.. turning airport on and off.. restarting computer.. running the assist me/diagnostics thing all to no avail.. tried disconnecting and reconnecting to my network.. can't get anything to go!
However if I take my laptop with me to uni I can connect wirelessly to the uni network fine.....
so thats the situation, if you need more details just ask and if you can help you're a king among men!\
im posting on here because i can't afford to ring the bloody toll line for mac support that they have in NZ ;\
cheers guys!