Buddies are right but don't panic...
Our friends are right when they said going abroad means abondoning 485 process provided that there is no other valid status when AP is pending...period.
According to legacy INS one should not go abroad if he has an AP pending even though he has a valid AP in hand. But I know many people traveling abroad defying all those idiotic rules knowingly or unknowingly. I know some people who left the country when AP is pending, had the AP mailed to them abroad and successfully entered the country with old/new one. Immigrant community is equally divided over this issue. You can find long running discussions if you do a search on EAD or Advance Parole. However, I am not very sure about leaving the country without having AP in hand when the AP is pending and having no other valid status. I strongly discourage this kind of contempt towards the outrageously inefficient legacy INS.
Anyway, since you applied for AP you can mail her the AP as soon as you get it. Fortunately, if the immigration officer at the port of entry does not notice discrepencies between the day your wife left and date of AP approval, which is not very unlikely, you are fine.
However, in the meantime I encourage you to explore all the options you have at your disposal and take advantage of the best one. Don't panic, you guys will be fine, hopefully. As someone said don't take this lightly and do post your experiences.