Tigers suffered a third defeat in four games when they lost 18-10 at home to Leeds Rhinos last Friday.
That came five days after an impressive victory against London Broncos, which seemed to suggest the 2017 league leaders were out of their midseason slump, but Aston reckons one win here and there will not be enough.
“We have talked about it,” said the former Sheffield Eagles scrum-half who spent the 2017 season at Leeds without making a first team appearance.
“If we are going to achieve what we want to achieve this year something has got to change within the next week or two and we have got to start winning games.
“Otherwise we are going to go through this year not achieving anything and just being a mid-table team.
“That’s not what we want to be, we want to be a top-five team and to do that we have to change something soon.”
There is confidence in Tigers’ camp they can match all their top-flight rivals if they get their game together.
But after they won their opening four games injuries began to take their toll and Castleford have not been able to find that consistency since.
Aston insisted: “We have shown we have got capabilities to unlock any team.
“But we slip up, we have knock-offs for one play and that can cost you the game.
“It’s just little things that are costing us big in the end. It is a tough one to take.”
Aston confirmed that was the focus of conversation after the game three days ago.
He added: “The main word we’ve been talking about for the last three or four weeks is consistency.
“That is what we are struggling to get at the minute, a little bit of consistency within everything we do. In the sheds that is what we were talking about. One week we will be gold, one week we are rocks.
“We’ve just got to find that consistency, so it’s back to the drawing board and keep working hard.”