It is never a good idea to buy fish just to solve a problem.
Snails are not a bad thing, they are an important past of the tank's ecosytem. Irt's when there are too many of them that it becomes a problem. The usual cause of this is over feeding the fish.Cutting down on the amount of food should reduce the snail population.
There are non-fish things you can try.
Find a glass jar with a screw lid and punch holes in the lid from outside. The holes should be big enough for the snails to get through but too small for the fish to get through. Place a piece of lettuce in the jar and put it in the tank last thing in the evening. The theory is that the snails will go in the jar to eat the lettuce but won't be able to get back out because of the spikes made when you punched the holes. Just empty the jar in the morning.
Or, if the place you live allows them, get some assassin snails. They breed much more slowly so won't be a problem.