Should i ask client for a job with better salary and title when company i currently work for has less to offer?

i work for company as a facilities supervisor(but so they don't have to pay me right they have reduced the positions description to damn near a janitor but ask me to perform task of a supervisor (which is cool i accepted it can you say survival job?) ok so i manage this site for a corporation (Genzyme corp ) to be more specific and on the web i see supervisors positions available and i feel id be a shoe in .but in today's economy i dont want to be seen as ungrateful for my job but strongly desire the advancement ive worked years for so how could i ask for the position in the corporation with all the bells and whistles ...like stock options and probably double my salary Help i don't want to let opportunity p me by?