A 500w psu without a 6pin connector?? Is this some generic power supply? Likely it really only puts out 300w but with such a low power system it should be enough.
You use the vga-dvi adaptor that comes with your video card to connect your monitor.
You use the 2xmolex to pci-e 6pin adaptor that came with your video card to plug in your psu to the video card.
Did you bother to even read the manual or are you just wingin' it?? Cause all that info is in the manual.