Slow speed in u torrent (3.4.8)

Hello,
my interner service provider is telling that the bandwidth they will offer is 700-800 but i am getting a speed of hardly 20 kB/s in u torrent(3.4.8).so what will be my actual download speed ?.sometimes the speed shows 700-800 kB/s in u torrent and even sometime it shows as less as it can .so how to increase the download speed i am really troubled my this problem.
please give a real solution so that i can apply it. i am hoping to get a real time solution from you