Andie, they're both valid options. Some people like to use their frosties ASAP rather than pay storage. Others like to do as many fresh cycles as possible to "bank" their frosties. If you get a BFP from a fresh cycle then when you start TTC again you're using 33-year-old eggs instead of whatever age you are when you start again. I'd probably lean towards the fresh cycle unless I felt like I needed a break from the stims (in which case I'd do a natural FET).

J.Bear, as Andie said, OPK = ovulation prediction kit. They are like HPTs except they detect the LH surge in your urine (instead of hcg) to help predict when you're about to O. Typically you'll get a +opk about 24 hours before O (usually within 12-36 hours).