Help newbie speed up internet connection G5 & DSL

I've been using the built-in ethernet card for my DSL connection, and it's been rather slow. would my connection be faster using the D-Link card my DSL membership came with? I rather not do that because i'm going to need it for PC we have, but i will if it will make a considerable improvement. any other suggestions? how much faster is broadband?
thanks.

Some one else my come along with an answer. But one thing you have to keep in mind is that your speed is also depnedant on your ISP and the distance from the central office. The farer from the office the slower your speed.