Check out "SATA-to-IDE adapter" at Newegg e.g.:
Some of the adapters you want are classified under "IDE-to-SATA adapter".
Thus, be careful when searching for such an adapter, because some
convert SATA data and power connectors to standard PATA HDDs.
Your host controllers are 40-pin PATA male connectors that mate
to 80-conductor Ultra-DMA ribbon cables.
You'll want to examine the proper adapters that convert standard IDE / PATA
80-conductor Ultra-DMA ribbon cables to FEMALE SATA data connectors,
with a separate connector for input power.
Those FEMALE SATA data connectors will then plug into your MALE SATA data connectors.
Thus, the proper adapter MUST have a standard 40-pin IDE / PATA connector,
just like the connector on your IDE / PATA HDDs.
Remember also to NEVER power a SATA HDD with BOTH the
standard SATA power connector AND standard 4-pin Molex connector --
if both are present.
Because most current SATA HDDs only have the SATA power connector
and no 4-pin Molex connector, you should limit your search to
adapters that also incorporate standard SATA power connectors.
With the right adapter, you should be able to upgrade your HDDs to 2TB,
assuming your IDE controller can address such large HDDs i.e.
48-bit LBA ATA controllers should work fine with 2TB HDDs,
using one of the preferred adapters described above.
Hope this helps.