If I bought a(n) USB wireless adaptor would i automaticly get wifi connection for my PSP? or make it stronger?

I am about to get a PSP but i dont have wifi at my house and noone around me has wifi, so i was thinking of a wifi adaptor but i have no idea what that would do, i was assuming i would get wifi but my father has told me he thinks it jsut makes the connection to others stronger am i right or is he?