Those look like Simplex Retrofriction shifters, which I have, and love. It looks like the bike is in fantastic shape, with a really interesting (and to my eyes, unusual) mix of components. I'm sure it would be more valuable with a complete Campagnolo grouppo, but since for many years Tommasini's came over to the states as frame sets, you see a lot of different components.
I don't see any fleaBay sold listings for Diamantes, though there are two on there now you can compare to. Of course the 'Buy it now' asking price doesn't mean anything unless it sells.
There are a few members here who own or have owned Diamantes -- hopefully they'll weigh in. Maybe post it in the 'Tommasini Lounge' thread so they'll see it. I can only guess what you should list it for, since I can't find any comparable bikes that have sold. Your best price will likely be on the 'Bay, though you'll have to deal with packing and shipping. If you're in a decent sized city you can try Craigslist, and I'd also pay a small fee for a premium membership here and list it in the marketplace thread. There are definitely a fair number of Tommasini lovers around here, though I'm not sure how many check the appraisals thread.