Bar and stem are easy enough to swap and widely available through places like the classifieds on here, retro MTB trading pages on Facebook (if keeping all the components period to the bike is important to you, there's no law which says you have to) eBay or online bike shops such as Chain Reaction or Wiggle. You're looking for a 1/18th (also called 1.125) stem and a 25.4mm diameter handlebar. I can't quite make out your existing handlebar from zooming in on your pic, but it looks to be an X-Lite X-Country. If so, and providing it is in good condition, you should have no trouble selling it on and covering a decent amount of the cost of your replacements.