That mobo can take a slotket card (~$20 USD)and a CELERON 2 1100mhz FCPGA (got mine for less than $100 CDN last year).
This runs at 1100mhz natively, but moving your bus speed to 133 should give you 1467mhz provided you really have PC133 ram (not PC100).
That would be your cheapest option, if you can find that stuff. Asus itself has a stotket card for that board (S370-133 I believe), but any will work...
