I have the MVP3C2 (same model as yours except that mine has UDMA66) and the only connector it didn't come with was the 16-pin USB connector.
From Pricewatch.com, I found that you can buy it (part # SKU-EPOXUSB) online from Lynn Computer Products for $8 plus shipping (http://www.lynncomp.com/motherboard.htm).
If that source doesn't work out, you might want to consider buying a USB add-on card that takes up one PCI slot. I remember seeing a twin USB (USB 1.1) card made by SIIG at CompUSA for about $20.
I think this will be cheaper for you than buying another motherboard. You'd probably have to pay extra for the USB connector even if you bought another motherboard since yours is an AT board.