My apartment supplies wifi, so I do not control the router. The is no administrator for me to ask, any.
Answers:
Then at hand really isnt much you can do. Talk to the apartment boss during business hours. You can try to move your computer, you may find a stronger signal elsewhere in your apartment.
It is also possible that here is a compatibility issue between the router and your wireless adapter. You could try updating your divers/firmware, or using a different adapter.