As it is wireless (I presume you mean wireless to a router) then are you getting a good signal? Try it closer to the router if not.
Have you set a network key to stop strangers connecting to it and using up your bandwidth?
Finally, run a speed test click here and see what you get. Downloading files is a 2 way process. If the server you are downloading from is overloaded then you will only receive a slow download no matter how fast your actual connection is.