Sounds like rubbish to me. The speed of the net connection you can revcieve depends on the distance you are from the telephone exchange. The further away you are, the more the signal degrades and the slower broadband speed they can guarantee you.
Of course that assumes they are using plain ADSL and not one of the rarer varients like VDSL or ADSL2.
Wanadoo would have to offer 8 meg broadband for a start (not all companys do yet) and you of course would pay for the privilige.
False info to get you to buy additional hardware by the sound of it - as khana says the speed depends on distance and exchange capability.....you'll also get a marginally faster speed using an ethernet rather than USB connection - but a wireless router won't make any difference
there is the fact that speeds of above 2Mbps are not suited ti modems/routers that are connected to your pc with usb. does your existing equipment connect using usb or ethernet?
This could be a reason why they say you need the router.
As I said previously, you would not be able to achieve much faster speeds with the USB modem , in fact originally they would not support 2Mbps, I believe they needed some sort of flash upgrade.
Wireless is not essential, but a broadband router and an appropriate ethernet adaptor, if there is not already one in your PC