Drewe Broughton had been recalled to the first team in place of Tom Pope, and Nicky Law replaced Paul Warne for what proved to be no walkover for the Millers at Grosvenor Vale.
Rotherham went in front just after the half hour, when Wealdstone keeper Sean Thomas was slow to a James Gray back pass, who then managed to blast the ball into the onrushing Le Fondre and into the net.
The Millers didn't have to wait long for a second when Ellison hammered home a fantastic 25-yard strike just before the interval.
The second half saw Wealdstone get themselves back into the game after 63 minutes when Ashe shot home from the edge of the box.
The game looked to be sewn up after 83 minutes when Drewe Broughton glanced in a header from substitute Stephen Brogans cross.
Wealdstone came back a second time with Ashe again getting on the score sheet after being set up by substitute Danny Spendlove.
Wealdstone pressed for the last few minutes but couldn't find an equaliser.
Wealdstone: Thomas, McCoy, Chappell, Gray, Massey, Ashe, Forbes, O'Leary, Mpi (Lafayette 86 mins), Ellerbeck (Spendlove 60 mins), E'Beyer. Subs not used: Beagle, Fitzgerald, During, Osborne.
Booked: O'Leary (45 mins), Gray (67 mins).
Millers: Warrington, Tonge, Harrison, Sharps, Fenton, Law (Warne 46 mins), Ellison, Broughton, Nicholas (Brogan 76 mins), Mills, LeFondre.
Subs not used: Annerson, J Taylor, Lynch, R Taylor.
Booked: Nicholas (73 mins), Brogan (90 mins).