Older motherboard w/Ide interface

Hello:
Using 4 year old motherboard w/AMD Sempron 2.5 Ghz, 80gb Hd, 1 gb ram,CDRW, Voice modem and security camera interface and XP OS. The system is used for the voice answering machine, internet surfing. With some 16bit programs I'd like to keep, which the 32 bit os nicely permits using, it appears 64 bit os would do away with the older programs unless the Cpu permits dual os of 64 bit and 32 bit. Use the CDRW to Image the HD.

To increase ram and HD size, I'd spend about as much as the cost of a new desktop sytem -about $300, compartively speaking newer interface would not limit the HD size as does the IDE.

What is recommended for new motherboard and processor?

Thank you.

Ram is 184 pin 2.5 volt. DDR 333/ddr 266 -slow but speed may not matter.
Previously, all of the 500 gb Hd I could find were refurbished, but thanks to your msg, looked again and found a new drive reasonably priced. The ram is a bit difficult as most of the newer ram is either 512 mb. or more pins than MB supports.

Thank you for your response!