Definitely need an upgrade... But which one?
The 550Ex and 430EX hotshoe flashes are very good general purpose flash units. However, for small product photography including gemstone photography, the hotshoe flash (although the 580EX and 430EX are great units) is not quite the right ticket.
I would get a light tent. There are many of these tents available on eBay for various prices. I hav found that there is really very little difference between the most expensive and the least expensive. You can find these tents (also called light cubes) on eBay under Cameras & Photo
> Lighting & Studio Equipment
> Light Controls & Modifiers
and then do a search for "tent"
Here is an example of a light tent. The size of the tent would be determined by the largest of your products you will be shooting.
http://cgi.ebay.com …ZWDVWQQrdZ1QQcmdZViewItem
As far as lighting the product, you can go with continuous lights such as incandescent or even the work lights sold in home improvement stores. These however, put out a lot of heat. I would recommend a set of two inexpensive strobes on stands. Using one on one side of the tent and the other on the opposite side, you will achieve shadowless lighting.
Here is an example of an inexpensive strobe unit which has a modeling light so you can see what you are shooting. This light (you will need two) has a light modifier (softbox) and a stand included. You can use the lights with the soft box (not using the tent) for portraits and for larger items which will not fit in the softbox. If you were a commercial photographer and were going to be shooting 8 hours a day, five days a week - I would probably suggest a more expensive strobe. However for occasional use, this unit should do very well. It is certainly not the only unit available, just one of the first I came across on eBay. The two strobes and a tent should cost about $250 plus shipping. This is less than the cost of a 430EX.
http://cgi.ebay.com …ZWDVWQQrdZ1QQcmdZViewItem
An interesting and really inexpensive solution might just be:
http://cgi.ebay.com …ZWDVWQQrdZ1QQcmdZViewItem
This kit uses flourescent lights which would reduce the heat problem. I don't know how powerful they would be but, the price is right.
Here is a tutorial on shooting jewelry:
http://www.home-jewelry-business-success-tips.com/photograph-jewelry.html
By the way, you really do not need a macro lens for shooting. Many lenses have a "macro" or "close focus" setting which will get you plenty close enough to photograph just about anything except insects or other really tiny subjects. many P&S cameras also have "macro" settings which will get you quite close to your subject.