The former Portsmouth manager, who was appointed as successor to Jim Magilton at Loftus Road on Thursday morning, had other managerial offers but admitted that the Rangers job appealed more to him.
"There have been one or two offers and I am grateful to those clubs. But this one appealed to me more. This has the potential to be a big, big club," he has said.
"If we need to buy in January then that will be the case. And yes, it will be my decision.
Hart has only been given a contract until the end of the season but has said that he not concerned by that.
"I like to work, and the opportunity to work and to come to a club of this stature so quickly was important to me.
"I am here for a short period - it might be longer - until the end of the season and that is time for us all to have a look at each other, to see if we like each other and to get on with it."
