@table681 he's giving you good advice. Provider "required" equipment covers a very wide range. It can be quite good, like a fritz!box, or it's a piece of "low bidder" heavily locked down junk, like the ADSL router I have. With my provider's router, while it does DHCP, I can't alter the range or even set a DHCP lease reservation. All I can do, functionally, is set a WiFi passphrase (the key) and turn WiFi on and off. The switch part of it is 100mbs which is fine for a single gateway interface - not so good for LAN use.
My solution was installing my router (with 1GB ports) behind their router. As a result I get roughly the same iperf numbers geaves has, on the wired side.
In your case, as recommended, a good low cost solution would be a 1GB switch or, (more expensive and a bit more complex) a router with 1GB ports, to put behind your providers equipment.
Okay I will test a switch tomorrow but in the mean time do you have any router suggestions you could give to me.