3 dongle bad signal ,needs a boost?

hi,im waiting for broadband to be installed,so i got a 3 dongle ,and the guy said i would get great signal in my area,but its useless,most of the time,is there any way of boosting the signal,i have a wireless router,with an aerial on it but the dongle wont fit in it,any help please.thank you.my pc is a laptop 2gig hd,and 2gig mem,anything i could download to help  stabilise the signal or boost it.

i had 3 mobile dongle before i got virgin broadband and apparently on there website i get the fastest speed where i live but it was really crap like 3 bars if i was lucky i tried to fiddle about with the settings but nothing worked.it's a con really.just hang in till broadband comes you'll be much better.=)