ADSL modems that handle bad lines

Hi tech list, Despite living in the inner suburbs, I have a dreadful ADSL sync speed; around 4.5 mbps, give or take 500kbps. I'm quite a long way from the Moreland exchange, unfortunately. There's not much that be done about that.. but I wondered if there are any ADSL modems that might work a bit better for me? I'm currently on a Billion 5200 which is getting a bit long in the tooth. Cheers, Toby