I was looking on ebay earlier and someone is selling a set of 146 alloys - I think they're the same as the Ti, can't be sure but have a look, there is a good photo of them. It is a full set complete with centre caps. I know you are only looking for one wheel but the price was only at £37 when I looked earlier tonight. Definitely worth a look for that price!
Just type in 'Alfa alloys' on the search engine and you will find them. The auction ends at 2pm on the 25th.