Lighting, Light Fixtures, Ceiling and Exhaust Fans - Mini Track Lighting Info.....Please Help!

I have a mini 12V track light set bought from Home Depot about 7 years ago. It has 3 MR-11 type fixtures and I'd like to add 2 more to it for a total of 5 lights on 1 track. The problem is that I can no longer find the right kind of fixtures to fit the track. The fixtures connect to the outside edges of the track instead of fitting in a slotted groove in the center of the track. You would slide them over the track and then tighten them using a collar to secure the fixture to the outside edge of the track. I don't need to have matching fixtures.....just ones that will fit this type of track. Can anyone help me locate this type of fixture or at least tell me if they are still on the market? If so, what are they called? Thank you!

If you remove a head there should be some indication as to the mfr. if not take it to a specialty lighting store (not HD) and they should have no trouble "tracking" it down for you.