U08s are fine riders. They are still popular, just aren't worth that much. You need to relaize that UO8 sold for less than $150, and the waiting list for them was weeks or months for a new one back in the 1970s.
If it was mine, I'd buy replace the broken spoke and true the wheel myself. then ride the bike while I shop CraigsList and eBay for an inexpensive front derailleur. I'd probably go to a Shimano, because they are prooven and more reliable than the original plastic Simplex and I am not interested in trying to make the bike into a Collector, I want it functional as a Rider. You should be able to find a working used front derailleur for $10, or a new one for $15.