Build Advice Recommendations for hardware upgrades ?

[Why_Me]

Any suggestions? I spoke to a computer engineer and he said that a branded power supply can support this card.

Also, any suggestion how much would I get for my old system configuration if I sell it to someone online?

You can give that psu a try. I'm no good at estimating the cost of used PC hardware tbh. The best thing to do imo is look on ebay for similar builds and see what they are asking.