70kb/s isn't bad at all.
More than one person shares your bandwith, you could never have up to 600kb/s for a download speed. Unless no one else would be connected to the server of your ISP at that time. Which is nearly impossible.
I have a 3mb line and I can perhaps get speeds up to 600kb/s. Because my neighbours are all connected to the same Server. Each ISP has different servers and some are faster than others because less people are connected. (I donot think there's any way of choosing the server you want on, if there is, wow, I'd like to know!)
By the way, I'm new to this forum. Look forward to posting here. People call me Raptor