If you don't have yoru F1 visa

stamped on your passport, and if you don't mind making a trip to canada, you can apply f1 there and if you got the visa, you can go back to China an apply your wife's F2 with her. By doing so, your wife's chance of getting the f2 will be bigger. But be careful, if you didn't get a F1 from US consulate in Canada, you won't be able to reenter US. So I guess you have to make choices.