Finding women's clothing for Frank is a relatively easy task, with the exception of one category. Shoes. AFAIK, women's shoes ONLY appear in Palisades Mall in Brand New U and Kicks for Her. Aside from shoes, other categories are found all over the Fortune City map.
You'll need women's:
-Hat/hair (I.E Space Girl Hair, Ladies Hat)
-Dress (I.E Summer Dress)
-Shoes (White low heels)
Wear all three at the same time and the chevo will be yours! :)