If you're wanting to do just you two, your best bet is to port forward again sadly.
If you're willing to have other players in your game (but on your team!), I can highly recommend the Flashpoint Levant and Grayflag servers.
Technically speaking you can get a dedicated server from providers like Fox3MS, but I don't think that's very reasonable for what you're getting up to, with their lowest price point being $43/month.
There's plenty of guides on how to port forward, and you should just need to open up port 10308!