I think there's some confusion here, but correct me if I'm wrong.
You see download speeds of 700kB/s (KiloByte per sec) when downloading
SpeedTest.net (or similar) is telling you you have 86.02 Mbps(Megabits per sec)
Sure, your ISP likely does measure/promise etc in Megabits (sounds better). 86.02 Megabits is roughly 11 Megabytes.
So you have a theoretic download speed of 11 Megabytes per second (pretty good).
The problem is there's two sides to this (at least). Just because you have that theoretical download speed, doesn't mean you can utilize it. If the server your downloading from limits speeds, or is at it's maximum, there's very little you can do to increase your speed.
Can you give us an idea of a specific example of a download for you?