What do your two and five year plans look like? You do have a plan don't you? If you don't take my advice and get one going. It will be a tremendous help if you can set some goals for your future and work towards reaching them. Also most people find it easier to get positive results if they have a path laid out and can keep track of their progress.
Education should be your number one priority especially if you plan on continuing up the ladder. Chipping away at your pre reqs over a couple of years is a good way to stay in the education game and start accomplishing goals. Extra certs are fine but don't drop alot of your hard earned cash on anything unless your sure its going to benefit you. There are always going to be people that want to separate you from your cash so be aware. Most agencies whether its a fire/EMS department or your local ER will usually pay for your classes or at the least meet you halfway on the cost. You should be able to look at your plan and know what you will need and when you need to get it done.
One thing that you should do sooner rather than later is get your CPR instructor cert. The red cross will help you with this and its a program that will allow you to give back to your community which is something that always looks good on your resume.
Knowing a little more about your direction if you have one will help us to better help you. Learning to network not only here but in your community is a skill that will always be a great help. Depending on your situation you may change your plans more than once during your life and having people available to help guide you is a plus.
Don't mind Brown I think he was dropped on his head when he was a baby. Plus he is one of them there foreigners that while he appears to be very educated and well versed at how things work at home he is often clueless and very stubborn when it comes to the way many of our US agencies operate especially the smaller ones. But he is a good source so don't discount him when he drones on about how inferior he thinks many of us are because we don't have an above average educational pedigree.
+1. My advice for the long term is to seek out a local EMS AAS program, and start at their pre reqs. Do the ENG, PSY, A&P, Pharm, etc. Your area may require you to go from EMT-B to EMT-I and then EMT-P. However, if you go to a college and do their EMS AAS, you'll be a medic afterward. That's how you get around regions that make you progress with baby steps. Think about it, I never took an "I" program. I went straight from B to P. If I were to apply for a job in a region that required their B's to first go to I school before a medic program, would they not hire me since I "skipped" the I program? Of course not. Besides, can't you enroll in a college EMS AAS with just a B cert? In my region, you can start out as a lay person. The first semester has EMT-B and a couple of pre reqs.
Why is it that you need to wait before taking the EMT-P program? How are things structured where you live?
Also, for quick resume boosters, take a foreign language, preferably Spanish in most areas. Progress to conversational Spanish if possible. You can then claim some fluency in that language, a definite plus. Also take the ICS courses. I think the ones to have are 100, 200, 700, and 800. At the interview you can tell them that you're positioning yourself for entry into an EMS AAS (degree paramedic). You wouldn't put down individual classes you've taken on the resume, maybe only that you're an undergrad at the college. What you can do is talk about the classes you've taken. They'll like that a mere EMT has already taken ENG, A&P, pharm, a foreign language, etc. Other than AHA CPR, don't worry about the alphabet cards too much at the EMT level.