Keep what you have as a grill and take your time to find a smoker that fits your needs. Don't rush into a purchase....
I bought an offset years ago because I wanted it. When it came to using it, it was not really what I needed. I wound up waiting to sell the offset to purchase a vertical.
Long story made short, think about what your actual needs are and when you select a smoker that fits them, ask for input to help guide your selection.
Humphrey's DownEast Beast W/BBQ Guru