I'm not quite sure whether I understand what you're trying to say, but this should be close (put into vimrc):
" bind leader-y and leader-p to clipboard copy/paste
noremap y "+y
noremap p "+p
(\y or ,y is easier to use than "+y which is the default binding)
`ps ux | vim -`, go into visual mode and select the stuff you want, then ,y to copy it to the clipboard.
If you don't use a clipboard manager then of course it will be destroyed once you :q out of vim. You could probably add the :q! to the binding to make it automatically exit vim once you 'confirm' (copy) the selection.