Websites and PageRank - PPC

I've been working hard trying to get Google to do what I want it to... of course I can't but that is my dream!.
The case in point is the linked website. We used to have PPC on the site and it did very well in getting hits - but precious little in conversions... now I wonder what the percentage of conversions have been lost by just removing the PPC.
There seems to be no dramatic hurry to put PPC back running - so it has to be site promotion everywhere and see if we can get the pagerank up..

Anybody got any other ideas...? I am certainly running out of them.. One of the hardest things to do is to promote your site successfully (and without breaking the Big Brother rules).