More info
The information
here might be useful. I believe that you would be eligible to apply for your husband in Pakistan the next time you go visit. Or, like mentioned above, you can file the I-130 from the US. Again, you are the sponsor, not your husband, so you will file the petition.
Either way, the subsequent forms (Packet 3, etc) mentioned in the link above will contain questions including whether the applicant is subject to the J-1 home residency requirement. If your husband has not completed his 2 years by then, he may be asked to wait before he can obtain his visa. I do not know if they will deny his application outright, or ask him to wait until his 2 years are up. Please keep in mind that if your husband ever visited Pakistan
while he was in the US on a J-1 visa, those short visits can also be subtracted from the 2 years.
Either way, being the spouse of a US citizen is generally one of the easiest and fastest methods of obtaining a green card, all else being legitimate. He may be placed on a conditional green card but that's normal. The US will also need to see proof of contact, not just proof of marriage, so along with wedding pictures and the like, be sure to save your phone bills and internet chats with him, as those are proof of contact.
Hope this info helps.
Oh - he will not be given a Green Card (conditional or otherwise) in Pakistan, he will be given an immigrant visa valid for 6 months. He has to land in the US before the 6 months are up, after which his Green Card will be mailed to his US address.