I'm Canadian citizen going to study in Taiwan for 2 1/2 months.

While there I plan to travel around Asian especially China. Is it best I apply for china visa while in Canada or wait till I have an itinerary in Taiwan and apply there? Here in Canada, it seems like I have to have an itinerary as it only allows single entry and double entry so since I have not booked anything I can't apply here. Please advise. Also, tell me how easy it is for a travel agency at Taiwan to apply for me.