UART serial problem

Hi,

I'm trying to read pixel data from the serial port on the de2-70 board. This is done via the UART serial core and the Nios II processor. However it appears that this serial core has a buffer of only 63 characters. When I use really low serial speeds it can receive without a problem. But when I increase the speed, the buffer gets full before I can read the data. How can I fix this? Should I use interrupts to handle incoming data or is there a core available that has a larger buffer? Any help is welcome.

Thanks