with adwords running your only getting 60 hits a day?...
er... sorry but your doing something wrong you should be getting more than that organic traffic... even if its just people trying to find you to tell you you have won the Nigerian lottery...
How much is your monthly PPC campaign costing if you dont mind me asking? are you tracking conversions using the e-mail page / submit button as a conversion? as with 10 enquires a day you would be eligible for CPA bidding rather than CPC (assuming 50% are e-mail enquires) which changes the ballgame a bit into your favour and helps stop the campaign running out of hand (with ours that are eligible for CPA we use a % of our margin so that we know we still make money on each google conversion).
with some proper SEO (not the
rubbish we get about 20 calls a day about) the site could do a lot better.. and without adwords bending you over...
You mention tips on SEO come with the sale yet nothing seems to have been done to the site as it sits... Backlinks, Active content (ok the reviews slightly count) ect ect
getting some more sites to link to yours would be a start (isn't hard with forums such as driftworks offering advertising and most car forums letting you advertise you link for free), you only have 1 site linking to yours at the moment which is a numberplate site with a similar template... the more google sees a site appear the more "important" it classes it as so the higher up the listings it goes. Trawling and e-mailing sites to be listed on their links page works but can be slow going (in experience 1/50 sites reply as theirs lots of robots out their doing the same these days).
hope you don't take any of this the wrong way just trying to help / get more info about the site.