I'm also always searching for upbeat Celtic songs with strong female roles - here are some of my favorites:

"Willie Taylor" on Deanta's first album: woman dresses up as a man to find her true love, finds out he cheated on her, kills him. Very peppy tune.

"Jug of Punch" on one of Altan's albums: sung by a woman weaving although the text is about how much men love drinking and "a tidy wench".

"Come by the Hills", I heard it first by Loreena McKennit: lyrical verses about golden bracken and a land where legends never die.

"Band O' Shearers": don't remember where I learned it, it's a happy song about about shearing sheep and flirting with your fellow shearers.

"Maid on the Shore", versions by Stan Rogers and Solas: great song about a woman who "takes advantage" of a ship of pirates.

"The Gray Mare", Karan Casey on her solo album "Songlines": a funny song about a greedy young man who loses his chance to wed a beautiful rich girl because he asks for too much.

These are all in the DTbase. There are more - I find that it helps to identify artists who like these kind of songs, and learn from them. For example, Karan Casey seems to like songs that have a positive outlook, so I look forward to the next album by her or Solas.