Which oil pump you need will depend on the year the engine was manufactured.
If it's a Mk1 or Mk2 GT you'll need 15100-11070, if it's a Mk3 GT or Glanza you'll need 15100-11071. If you have a Mk3 GT from the first month of production, you may need the earlier oil pump. If the engine has previously been replaced and you have no idea of the year, then you'll have to pull the pump off to check which type it is.
You can go direct to Toyota or Tuning Developments can get OEM parts.