Yes it's probably PCI-e 1.0 and with a BIOS upgrade (try the manufacturing company website) it will probably be able to run a 2.0 PCI-e card.
I would however replace the motherboard since it's pretty old and I think it's not worth spending money on it.
About the PSU I'm not sure but I think any motherboard can handle whatever wattage the PSU provides so no need to upgrade board just to upgrade PSU
Thank you for the response. I guess my options are a lower card or the additional cost of a low end motherboard.