I think there is a guy on the macgregorowners site who made a mold to layout a new fiberglass poptop (maybe that's you?). You might want to search the archives there.
If you have the old pop-top, and the issue is just that it has been repaired so that it is heavy and ugly, I'd try finding someone who does good Fiberglas work - perhaps the excess weight could be ground down, and the outer surface smoothed and painted with a good epoxy marine paint. If the surface was non-skid, that can be re-done using a special rubber "mold" which is laid on top of wet fiberglass.
If you don't have a boat repair yard around, you can also look for good fiberglass guys at some vintage auto shops - the pop tops on classic VW camper vans were fiberglass, as well as the bodies of corvettes, etc.
You might also want to look around for "Good Old Boat" magazine - if I recall there was a pretty big layout within the past two years or so about a Venture 22 restoration - that article may be available via an archive or reprints, and it may have some useful resources for you. The classified section of that magazine often has good resources for folks working on older (or newer!) boats with a constrained budget.
Try looking up an old site called something like www.sailingsmall.com . I think his name was Brian Gilbert???. He restored an abandoned 2-22 and maybe redid the top and all . He had lots of photos and remarks and even a CD to buy
Maybe I can help, I have a few Venture parts listed on ebay right now. I have the forward hatch, cockpit aft storage hatch, the companionway hatch, the sliding top hatch, the pop-top (which I haven't listed on ebay yet), and the mast. The listing for the mast ends tomorrow and the rest end on Tuesday. I also have a trailer that I will be listing on there this week. Hope this will help. My store on ebay is Re-Sail Gear.