Welcome aboard, Sunny
That part number is a Grady part number. While you may find it by googling, your best bet would be to simply contact your local GW dealer (or any dealer, for that matter... but it's nice to keep your money local) and they can get it for you. However, it is not a part that was MADE by GW so you could track down the actual manufacturer and buy it through a retail store/online. It might be Perko... maybe Southco - without seeing it, I'm not sure. Look for some ID marks on it.
FYI... you're a "third time" poster. You've made a couple posts in the past...