Your best option is the Picosure laser. This will remove your tattoo in usually 6-8 treatments. Since it is a cover-up it will take a few more treatment will probably be needed. The Picosure works well with a varity of ink colors. Find a doctor with a Picosure laser.
Pico second laser for tattoo removal
With a larger, denser tattoo, it is better to go with the more advanced picosecond lasers. Based on the image, anywhere between 6-10 sessions is likely. Good luck!