Engine Oil Cap Stem Broke

[Ballz]

I wasn't aware of this issue when I bought the car but my oil cap (the stem more specifically) does not stay attacked. The junk around it is JB Weld which an Advanced Auto Parts guy suggested. It obviously did not work.

Is there a sealant that will actually hold the peice to the valve cover. My thinking is I need the to buy the whole valve cover.

Any suggestions?