Accidentally locked myself out of my wireless internet how can i fix this proble

Hello,
I recently secured my wireless network because a friend that was staying with me was abusing the privilege of using the internet (playing games, and not looking for work)...so I secured the network so I could still use it but he couldn't...now that he's gone I tried to change it back to unsecured and now I can't get online myself...I've managed to lock myself out! I guess I'm getting what I deserve, but I desperately need the internet to look for work now myself and I need your help (PLEASE) to help fix this mess I've created. Thank you in advance for any expertise you can give me.