FSH of 18.5

I am 39 and have a 17 mos. old son. I got pregnant w/him when I was on birth control so didn't imagine I'd have trouble conceiving again. When my son was 7 mos. old I got pregnant again but miscarried at 9 weeks... after a few more months of ttc & worried about my age we went to see an RE. In Nov. we did an iui w/injectibles (think i only had 3 follies). that iui failed. we took a month off (mainly to scrounge up the $ for another cycle as our insurance does not cover any infertility treatment).. went for my ultrasound & bloodwork for this new cycle & then got a call from my RE that we have to cancel b/c my FSH is 18.5.... she seems to think our best hope (although I got the impression she felt our chances were slim)was to use estrace to hopefully suppress my FSH and then do an IVF next month (if i respond to the injectibles)... my hubby & I talked about it for hours & have decided that we will try do an IVF next month -- we can manage (barely) to come up w/the $ to do it-but my question is - are we just throwing our money away? my heart says its worth it for ANY chance at all but my head says i have to be realistic & think of our family now.... guess I am just looking for stories of women my age who've had success w/ IVF even after a high FSH...also I understand that there's nothing to be done about the FSH but is there anything besides the (healthy diet & exercise, avoid caffiene, alcohol, smoking) that I could possibly be doing to improve my chances????