Dell xps 420 power supply change

Hello, im kinda new in pc building. i have Dell XPS 420 with the original 375W PSU. i want to upgrade my GPU to GTX 960 4GB and i need a higher power PSU. and i was looking for PSU that would fit the XPS 420 and has connectors to motherboard etc etc. i found a 500W silent fan PSU that has the connectors that go to motherboard but no connectors to the small screen in front of XPS 420, i was wondering if that matters, as well as if PSU with 

would fit in the XPS 420 

this is the product i was looking at https://www.ebay.co.uk/itm/Black-500W-12CM-Silent-Fan-PC-Power-Supply-ATX-Computer-PSU-500-Watt-SATA-24-PIN/192565026066?hash=item2cd5c51d12:g:7wIAAOSwYf9bHfGT