A bottom end rebuild would be best, also you should have the crank measured, journals maybe tapered so a regrind maybe in order, and if you have the crank out then you might aswell do the rings too.
Norris designs do a set of rings for about £40 and they do international orders too.
http://www.norrisdesigns.com
As for bearings and automotive engineering firm will be able to supply them, I found that Nissan often sell them cheaper than pattern parts!