I believe you are throttled.

You can try proxying up. It's not free but we have 1 or 2 forumers who are providing such a service. Well, just one, the other is in beta.

Virtual's VPN service: http://forum.lowyat.net/topic/377044 (RM30/30days)

Duock's beta VPN: http://forum.lowyat.net/topic/383630 (currently full, keep in view)

And if you have time to do some casual reading: http://forum.lowyat.net/topic/345583 (discussion on how to bypass throttling)

Drop on by the Networks + Broadbands subforum, we got lots of threads you can read up on.