McCoist confirmed over the weekend that he was keen to bring the experienced Spaniard back to Ibrox, following a successful season in Glasgow in 2007/8.
However, the two clubs are still a long way apart in their valuation of the player and McCoist admits further negotiations will have to be held.
The Rangers manager is nevertheless hopeful that progress will be made and eventually a transfer will be announced.
"Carlos Cuellar is very high on the list," McCoist explained.
"I know negotiations have been going on between the two clubs.
"Carlos is a player we would certainly like to see come back but there is a lot of water to go under the bridge between now and then.
"He is still an Aston Villa player and they are aware of our interest. There has been dialogue but there is still a lot of work to be done on that one.
"It has to go through the right channels and the clubs haven't agreed anything at all as yet.
"That would give you an indication that there is still a lot of work to be done. It's one we will continue to push along."
Source: Team Talk
Source: Team Talk