I read the specs of your pc and some threads on forum about the psu.
And I think you should upgrade you powersupply. At minimum a corsair cx430 would do the work without any issue.
As your PSU is not of good quality and doesnt has a 6-pin pcie connector (if it was a good quality one you could've used a molex to pcie convertor, but it isn't) thread about you psu
I personally like corsair psu as they are good quality and budget friendly. I would suggest a cx500 or a cx430. I have seen some people recommend some seasonic psu as they are good quality too (no personal experience).
I think you should check whether those powersupply can fit in you pc (check dimensions).
Following are the links to the powersupplies: Corsair CX 430 Corsair CX 500
Components of you pc require certain wattage to run. On low load they require less wattage and on high load they require more wattage. A good quality psu supplies the wattage mentioned whereas a cheap one delivers way less wattage.