Can't connect to wifi please help!

I've been trying to connect to my new wireless router, D Link dir 836L, for a couple months now. It worked great with my old router but old router doesn't work any more. I've tried everything from letting it automatically get my router info to manually inputting the ip address and all that but still doesn't work. And when I tried to manually do it, a screen popped up and said that ip address is being used. I couldn't record stuff when I choose record by channel or time however I could record stuff using manual option so I wasn't too worried about not connecting to wifi and tivo but now even that doesn't work any more. I am going crazy and this comes at a bad time because I want to record the NBA playoffs. Please help! I get the N13 and sometimes N02 errors