If you have pitched Champagne yeast I would forget about any further pitching of beer yeast. Wine yeasts have a positive competitive factor which means they kill competing strains, namely beer strains. Wine yeasts CANNOT ferment Maltose (Glucose-Glucose) or Maltotriose (Glucose-Glucose-Glucose), only beer yeast can.
So if the wine yeast has killed the beer yeast you are pretty much stuck with whatever longer chain sugars are left. One solution that MIGHT work is to use some enzyme to try to bust those sugars down into Glucose which the wine yeast CAN ferment.
Something is always fermenting....
"It's Bahl Hornin'"
Kegged: Bourbon Barrel Imperial Stout
On Deck: German Lager