If you are only a short-timer in that apartment, then a USB modem is probably the way to go. Any city of any decent size will have at least one big electronics market where piles of vendors will have shops. Take a Chinese friend or colleague along, bonus points if same is a techie. I don't know what these things cost.

If you will be in the apartment for 8-9 months or more, or if your usage might be heavier than you are now anticipating, it might make sense to compare (a) the costs of the USB modem + prepaid data service for the relevant length of time, vs
(b) getting a phone line installed/activated for ADSL, and then using it wired (or with a local single-point wireless router). Normally line service-based internet comes with a telecom company-provided router and unlimited internet use--paid monthly, cost depends on speed required.