He will most certainly have trouble gaining 10 pounds of muscle in one month. He is already 2 years into training, so any type of "newbie gains" he could have hoped to have gotten are gone unless he has been doing little to nothing in the weight room (and at 145 pounds thats not too unlikely)
OP, you need to get rid of this mentality that you will gain what you need to gain in a month. Most of the bigger people on this site have been at this for 5-10 years or more.
Focus on eating 1 - 1.5g protein per pound of body weight every day, find a program you can stick to for the next several months and GET STRONGER on it.