I do plan on integrating opentable, that'll be the next feature I add, if I stick with it. It's pretty much a labour of love at this stage, HN has convinced me I'm fighting a VERY uphill battle.
Restaurant management, along with freemium services on the site, was where I was hoping to make money eventually. Sadly, as you and others have pointed out, restaurants live on the breadline, so I think I picked a bad market!
In terms of SEO, think I posted the easy wins I did on another comment. "newtown" was just an example of a made up place for illustration purposes in the original post. That's cool that I'm in position 16 for Rathmines, I was down in the 50s last time I checked (Rathmines is a cool area with plenty of restaurants).