If you have a 1Mbps connection, that is the maximum (theoretical) speed at which you can download data. With an asymmetrical connection (e.g. ADSL), the upload speed will be slower; with a symmetrical connection (SDSL), it will be the same.
Programs, such as "Onspeed", which claim to improve data transfer speeds do so by applying compression to the data. This can deliver some improvement with data that isn't already compressed, but files such as JPG images which are already compressed won't show any improvement. The technology is better suited to slow "dialup" connections than to broadband.