you are doing the right things, and a few threads down there's another about a woman not being able to orgasm from sex alone that has some good info - a LOT of women have trouble reaching orgasm and it's something a lot of us have had to learn
get this book: For Yourself: The Fulfillment of Female Sexuality by Lonnie Barbach
http://www.amazon.com/exec/obidos/AS...049415-3759318
it has a lot of good information, tip two: get a little vibrator, once she gets over the initial embarassment, she'll like it