Madejski is prepared to back his manager in the January transfer window following the team's sluggish start to the season.
"If you look at the summer, Man United and Liverpool spent £40 million each, we spent hardly anything. So by definition we're losing ground.
"So for this club to be ambitious we've got to be acquiring a minimum of three substantial signings every year.
"As time goes by those signings will become more expensive. For us to make those signings players have got to want to come here.
"They've got to see the ambition, it's got to be tangible in the form of expensive signings, a bigger stadium. Everything about the club has got to meet the demands of the modern Premier League player."