Tita, you might run across a streptocarpus at a nursery like Swanson's or Molbak's...but I'd contact the Puget Sound Gesneriad Society to inquire about a local source:
pugetsoundgesneriadsociety@gmail.com

However, a specialty plant like that may require buying online. You could do a web search for vendors. Check out Logee's:

http://www.logees.com/products.asp?dept=146

I'm somewhat familiar with Kartuz Nursery in SoCal...I just checked their site and it looks like they sell streptocarpus only in a "grab bag" manner - 3 of their choice for about $18 or $20, depending on whether they're named/unnamed cultivars:

http://www.kartuz.com/c/1GES17/Streptocarpus.html

Patrick

Ok...I've got to quit "researching" gesneriad sites or I'll get hooked on these plants again!

I found they are offerred on eBay (what isn't?!). I also found that David Thompson is apparently a respected streptocarpus hybridizer. This eBay seller sells some of his cultivars.

Here is a link that might be useful: Streptocarpus on eBay