Sorry for the delayed response! I've been so busy these last couple of weeks. Well given your work experience, you probably have some breathing room with your GRE scores. At an information session I attended recently, I was told that the GRE scores are most important for students coming straight from undergrad with no work experience. So an amazing GRE score can help compensate for little work experience to some extant, BUT you should still try your best. I only say that to take the pressure off, but it's certainly worth preparing for!!
I recommend one particular Youtube Channel for GRE prep. Search "Keshwani Prep" and it should come up. He has a playlist of 200 videos in which he solves every math question found in the official guide. It takes a while to watch them, but it's definitely worth it.