Based on your qualifications, finding a job shouldn't be a problem for either of you, no matter where you'd like to work. You both have a lot to offer an employer, and your girlfriend's command of many languages is especially helpful. The possibilities are wide open.

The best strategy would seem to be that you conduct separate and independent job searches. Even if you both apply to the same large international company in your areas of expertise, we don't recommend that you tell employers of your personal situation. Since you're not married, it probably won't help to bring your relationship to the forefront while interviewing. Sometimes companies are willing to assist a spouse or significant other of a valued employee in finding a job, but rarely will they do it for someone new and untested. It's a risky proposition for them and usually not worth the effort and expense.

Since your preferred location is Costa Rica, focus your efforts on only that country to start. It doesn't make sense to try for jobs in different countries, because if one of you does get an offer and the other doesn't, you'd have created the exact situation you say you're working to avoid. It would be to your advantage to visit the country and see firsthand exactly what the job market looks like. Don't let negative thinking about economic troubles stop you from trying to realize your goal. After all, economies the world over are ailing, but people are still finding jobs.

Finally, be prepared that only one of you might find a job right out of the gate. If you remember that the situation is temporary and can handle it emotionally and financially, the other will have time to find the right situation a little further down the road.