It should come with the psu. If it doesn't, you psu can probably deliver the necessary wattage for the card your getting and you will need to upgrade psu.
Check the specs on your graphics card from the official website and which connectors it needs. Check the specs for the psu and to see if it comes with the right connectors for your GPU
If you are using a modular PSU, the cables will be provided with the power supply. The modular cables are not universal. The specs on the power supply will list the number of each cable provided.