I use a £15 ADSL+2 modem router (e-buyer Guru model that's a rebadged Safecom product) quite happily with TalkTalk.
There's plenty of advice on its website about setting up and configuring routers (one or two well known models won't work). See:
click here (for configuration)
Don't forget that the router's username and password are your phonenumber @talktalk.net and the provided password (mixture of letters and numbers).
However, to enter My Account it's your TT e-mail address and password.