How do i speed up my internet?

i have a radio internet by rhino communications and at first i got 3.0 mbps easy and even alittle more but now im struggling to keep it in the .70 mbps i did do a system restore because my pc had a virus on it. i have a router connected to the pc so i can get internet on my ps3 and ipod as well but i disable the wifi so i can download things faster and that only gives it .10 more so help me please.