Hi.
Marie is right in what she says regarding there being many possible reasons but my main guess is that you have either been hit by Panda or that your old site had better content.
Firstly I would say that if you have had a technical site audit carried out that it was either a poor quality one or that you haven't actioned the recommendations.
There are two full versions of your site on different domains:-
http://www.waytekwire.com
http://order.waytekwire.com
These domains mirror each other exactly and both home pages are claiming to be the canonical version.
The content is extremely thin and your site is pretty much an example of what the original penguin update was released to combat. This product for example has no description and no worthy content on the page - http://www.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-/
This product is not alone on your site, most of your products have no descriptions.
Also your site is suffering from a common ecommerce issue of your products being viewable with or without a trailing slash and there is no canonical tag in the source to say which is the canonical version. i/e:-
http://www.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-/
http://www.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-
Show the same content. in fact the same content is shown on all of these urls :-
http://www.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-/
http://www.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-
http://waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-/
http://waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-
http://order.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-/
http://order.waytekwire.com/item/48006/LED-CLEARANCE-MARKER-1-5-
As Marie says, there could many possible reason for your ranking drop, my guess is that it is a combination of multiple reasons. Until you get the very basics sorted you are going to struggle in cracking this issue.
My best advice would be to pay for a really good site audit and follow through every recommendation. Failing that, sort out your site canonicalisation issues and give every single product a good description.
Really sorry for the bad news but hopefully it helps point you in the right direction.
All the best.
Ade.