There's not much to go by in this case. One of you will have to be an US Citizen for the I-130 to happen. An LPR can also do this, but could take longer (something about visa numbers being available).

I don't think it matters whether you file in or outside the country. You'll need a stable address to file from (so you'll receive USCIS's receipts, requests for evidence, or paperwork of the sort).