Slow Broadband speed

[Ricwin]

One of the most common causes for slow internet speeds is using extension sockets/cables in the property. Get rid of long lengths of RJ-11 cable, dont use a phone socket in the living room.
Instead connect the router to your master socket (or even better, the Test Socket) normally located by the front door to the property.

Replace the filter with a new one, these do degrade and as mentioned above can cause plenty of issues.

A new router is not likely to make much difference, especially if the line speed itself is poor. I would also look towards other potential issue, get onto pingtest.net and speedtest.net to run some tests and check the quality of the line as well as the speed.