Hi,
Just bumped up my bid a bit as I've seen that you've tried to solve one of the issues before on the joomla website and your customised (but very attractive) template is the cause which is going to make this a little more tricky.
I have over 10,000 Zen cart module downloads to my name, am british and in the UK, I used to be one of the developers. I'd need to see the website first, as I have no doubt that I can do it, I'd like to confirm that it would be a price and speed that is acceptable to you.
Thanks
Philip.