You've come to the right place. I think we can help you out.
First, many mail order and internet retailers advertise in the pages of
FineScale. There's an Index of Advertisers toward the back of each issue, just in case you're looking for a specific company or product.
Second, try the link over on the left side of this screen under "Community" for HobbyRetailer.com. It may help you find a local hobby shop that will fill your needs. Also, under "Community" clicking on "Links" will take you to several pages of modeling links, many of which are for manufacturers.
Third, if you're really into car modeling and don't subscribe to it already, I recommend checking out our sister publication, Scale Auto
http://www.scaleautomag.com/
Finally, if you're searching for a particular item/product/whatchamacallit and none of the above sources help, just come to this forum and post a "Does anybody know where I can find a....." message. Another member may be able to point you in the right direction.
Best of luck--and welcome back to the hobby!