The bush is probably a standard bronze bush pressed into the housing. To get the required size you will need to measure size of shaft and hole the bush goes in, it will probably be imperial size not metric.
Is bush flush with bottom of hole? If not you might be able to get something under it and pull it out, or partly pack hole with grease then find or make something that is a good fit in the bush and hit it with a hammer; this will compress the grease and hopefully push the bush out. If there is no gap under end of bush in hole then you will need to bore it out or cut it and use cold chisel to get it out.
Difficult to say what is best solution without seeing part in the flesh, photo is a bit blurred.