New modem or what

Hello All

Right im trying to sort out my D/L speed Im on a unlimited pakage . But not sure what the fastest the D/L would be if you was the next house to the exchange But im only getting low speeds untill now I have not worried but now I have a box that can stream stuff from my seedbox its a problem. And i wondered if changing my modem/router would help seeing as iv had it since around 2002-2004?
And if so can anyone suggest a good one to get?

regards Andy

if you are on an ADSL2+ package and within 100m of the exchange building by cable distance then 20 Mbps

Without data from the actual modem you have it is impossible to judge