Need to convert patio door lock to a keyed door lock

Hello:

Here are the pictures of my current patio door lock to a keyed door lock. My current lock only locks on the interior and can only be done "by hand." I would like to change the lock so that it still can be locked "by hand" on the interior but also be locked by key on the exterior.

In short, I'd like to be able to leave my house through my patio door and lock the door behind me. I'm not sure which one of your products to order. Please help!

Thanks so much!
Katrice

Thank you for your response! Would I be able to use the keyed lock that you recommended with my existing handle? Or would I also need to purchase a coordinating handle set? If I must purchase a handle set, which would you recommend?