Where can I find a tail lights and front turn signal lights for a 1990 Volvo?

Most aftermarket stores(Napa, Checker etc) online or in town wont have what your looking for. You need to find a Keystone type place that makes those kind of old parts. Try http://www.lkqcorp.com/index.aspx and see if you can contact someone from there. I think they only deal with dealers not retail customers but that compant should find what your looking for.