If they're standard cartridge bearings they should just press out. Then you can take the bearing to your local bearing supplier, who should be able to measure it up for a replacement.
A lot of times, they have the bearing number on the plastic dust covers. Might need a magnifying glass to see it. The bearings in the levers are very small, pulling them out may be a challenge. Enduro sells bearings and might have a puller of the right size too. I got the bearings for my Arch's from them.