Ethernet accerlation problem

Hi,

I have made through ethernet with NIOS 2 processor, and get a data rate at 100Mb/s. But now I need it more than 400Mb/s, one solution, I think, is to write all the drive in hardware rather than configure the MAC, but seems like it really takes a lot of time. Is there any other solution which achieve such a high data rate? Is PCI-E applicable?

I use Stratix III and Cyclone III, both works.

Thanks