I take it that your Ouachita and softie are in seperate tanks, because they're not really the best of tank mates...
Nice little musk setup though. I stick with shallower water for them when they're small, but they enjoy the slightly deeper stuff when they've grown up a bit.
Best bet for finding a female ouachita I'd just keep an eye out in local pet stores and various classifieds, have a bit of a trawl (they all tend to be listed as mississippis or false, but there are a fair few ouachitas in there). As long as you're proficient in telling apart Falses, missis and Ouachitas there are plenty out there in need of homes!
Where are you based?