Your question is not clear: you are on H1 and your girlfriend is a permanent resident who will file for citizenship?
Are you married? Your question puts the cart before the horse: you could marry before or after she gets her citiznship. After she gets her citizenship, then and then only can she sponsor you on K1 or something. There is no way the two of you will get your citizenships "at the same time." You have to first get your green card. You can't adjust status from h1 to a citizenship. One wishes that were possible, but alas it's not.