In the first half, Mark Duffy played a reverse to pass to Cotterill, but the latter's shot was too weak and was comfortably held by Fulham keeper Marcus Bettinelli.
Roadallega went close for the visitors, but his effort flew wide of the post after he got on the end of a Hoogland cross on 20 minutes.
Jonathan Grounds should have perhaps have given his side the lead just after the half-hour mark when he flashed a header wide from Cotterill's corner.
With the first period drawing to a close, Cotterill curled an excellent effort beyond Bettinelli from around 25 yards out.
Hoogland evened the score up just after the hour mark with his third of the season after good work from Fernando Amorbieta.
Colombian striker Rodallega then gave the rock-bottom visitors the lead when he raced onto to Ross McCormack's through-ball to fire in with a powerful effort from a tight angle.
Fulham finished the stronger of the two sides as Kit Symons recorded his first victory as caretaker boss.