I ride a small Giant - I am 5'4" tall, 30 inch inseam, rather long in the waist rather than short like a lot of women. You almost don't have to worry about standover height with this bikes with the compact geometry - the top tube just doesn't get in your way when it runs down. You need to measure your top tube length and compare it to the top tube length for a Giant. This will start you in the right direction. Then go ride some bikes and talk to a dealer, they will have a good idea how the bikes fit people.
Compact frames work well for a lot of ladies, so you might try it and see. I love my Giant TCR - it is SWEET!