Seeing as how you have NR EMT P, you are in a good position. As far as your fire certs, depending on where you go, you will more than likely have to redo a fire academy.
Are you set on being a fire medic or would working only as a paramedic intrest you?
What states do you have in mind? There are tons of options out there, if you give a little more focus, there are plenty of people here that can give you some great advice and very detailed information.
Having said that, here is my opinion if I were in your shoes. I would do my damndest to come over as a medic, get some experience, get a feel for different areas and then start trying to cross into being a fire medic if that is your ultimate goal.
Now relocating can be very expensive and wages are not that great. But if I were to cross the pond, I would find a service that was hurting for paramedics and was willing to pay a sign on bonus.
It just so happens, Acadian ambulance is still paying paramedics a 20K sign on bonus. Now first of all, I do not particularly care for Louisiana, however if I were making such a big move and needed a job, using them for the two year committment would not be beneath me.
They will give you 10K up front for relocation/sign on, 5K at completion of month 12 and the final 5K at completion of month 24.
I would think long and hard about this opportunity as it is one of the highest sign ons for medics I have seen in years. Now mind you, Louisiana EMS is not top notch by any stretch of the imagination, the state itself is not all that impressive, however the cost of living is very low, you will get a ton of ALS experience, and the $$$ will help absorb some of your moving costs.
While sitting in that position, you can take your time and start exploring all the other options and states.
Just my .02 cents