How can we get a Las Vegas algorithm from a Monte Carlo one?
First, the algorithm should run forever; since you are going to stop when you have a correct answer. By this way you can guarantee that you never outputs a wrong answer. So, probability of error is zero.

So, the algorithm should be as following:

Algorithm LA
1) for i = 1 to infinity do
2)     solMC = MC(n)
3)     if solMC is correct
4)         return solMC
5)     else
6)         solMC = MC(n)
7)     end
8) end


Also, verify the solution from MC(n) by the given in the question which takes t(n) running time; because you don't know that monte carlo algorithm outputs correct or not. Also I removed the else condition, I don't see it is important here. So, the algorithm should be edited as following:

Algorithm LA
1) for i = 1 to infinity do
2)     solMC = MC(n)
3)     answer_from_verifier = output_Verify(solMC)
3)     if answer_from_verifier is correct
4)         return solMC
7)     end
8) end




Now, the expected running time is: 

$E[X]= \sum_{i=0}^{\infty} (1-\gamma)^i \gamma (i+1) (T(n)+t(n)) $

$= \gamma (T(n) + t(n)) \sum_{i=0}^{\infty} (1-\gamma)^i (i+1)$

$= \gamma (T(n) + t(n)) . 1/\gamma^2$

$= \frac{T(n)+t(n)}{\gamma} $