Metro-E bandwidth issue

I am having a hard time figuring this one out any help would be greatly appreciated.

I have a 50Mbps Metro-E pipe through At&t that sits with a Cisco 1811 router at one end and at the other a Cisco 3550 Layer 3 switch.

I have configured both devices and established a stable connection however I cannot average more than 2.5mbps up and 1Mbps down. I have verified that all interfaces are at full duplex (100mbps) and AT&T tested all of their equipment and lines up to my termination with an all clear from them.

I am drawing a blank from here.

Please let me know what you guys think.

Thanks.