Get her some nicer wheels, with an 8 speed cassette and chain, new rear derailleur, and some budget shifters. It will feel like a new bike.

Check that her stem is in far enough. Looks a bit wrong from here.

My girlfriend at the time was riding some old Ross clunker or something and wanted to try a race for a lark, I managed to fit my tubulars on there with a little brake pad adjustment. Probably knocked 4 pounds off the bike.