1) Sounds like someone's vandalized/cannibalized your printer. Replace the missing parts asap as the heatsink need to be fitted properly. Part that can be printed may be found on Thingiverse. The bolt should available from any hardware supplier. It is an M3 bolt, I can't recall the length though so you may need to remove the second one to measure it (NOTE: capscrew lecgths are determined by measuring only the shaft, no the cap!)

2) 230 is way too high for PLA. Its likely that PLA got burnt has caused a blockage. You may need to strip the offending nozzle to clean it out properly.