Trying to use E1200 Router as AP

OK, got a big house.  Bought a new Linksys WRT router which covers most of the house.  My office has a CAT5 cable from the main router, which I had an older Router that I used as an access point,  but I was only getting 12 MB or so downloads but I can get 100MB hardwired and 60 MB from my new router. 

The basic problem is that I wanted to set up a new AP, but I decided I would buy a E1200/N300 router,  because I want high speed wifi as well as 4 hard wired cables.  Could not find a AP like that. 

I configured the main router for DHCP  to give up to 192.168.1.100 and assigned the new AP to 101.  I turned off DHCP on the AP, thinking that DHCP would pass through (like my old router/access point) the DHCP request and pass the new IP. 

Thing is,  no luck. 

So did I buy someting that won't work  ?  Am I missing something ? 

Andy