I think you have good chances due to proven fertility. That does indicate a positive sign in my opinion. I would suggest you go to a high fsh friendly RE. I do not think your wife's fsh is incredibly high. Mine has never been that low, even at a much younger age and ***MENTS I found success -but that did take me several years of monitored cycles trying everything but the kitchen sink** END MENTS. It is higher than "normal", sure, but not impossible to work with. I definitely wouldn't call it shocking if you guys conceived again, even soon (so keep trying in the meantime)! The length of time it took for you to have your baby boy could be an indication that this is not a new issue. You probably hadn't had your wife's Fsh tested previously. I really would not panic yet. It's imperative you get an antral follicle count done. That will be very indicative of what you are up against. Also what were the other levels E2, LH, AMH if tested? Again it might take several cycles and lots of determination but please do check back after your appointment if you have questions.
Off the bat I probably wouldn't go with a high stimulation protocol if IVF is suggested. And so you know some centers have a cut off of FSH of 15 in the cycle you would have IVF done. Meaning over 15 they would make you wait for another cycle to begin. FSH does fluctuate so that may or may not affect your situation.
The "Over 40 board" has lots of great info as well and is much more active than this board.
Bottom line is I think it's way to early to think about donor eggs but definitely a good option to know about.