If you have standard bobbin cases with the finger you should be able to replace the Bobbin cases for a couple of pounds each, I know this from when I used to have school contracts to service machine mainly Bernina, unlikely you will be able to buy spare springs because the dealer has to buy so many in they could be on the shelf for years, try a standard right finger bobbin case to begin with rather than buy the actual Bernina which are very costly.
Ken
drivewithklen
October 2010