The loss against the four-time European champions, as well as Harlequins in the first round, means Eric Elwood's side will go in search of their first victory in the competition against Gloucester on Saturday, and O'Halloran believes a victory could reignite a flailing season.
"We have to target every game at the moment because we need a win," said O'Halloran.
"There is such a build-up to the Heineken Cup games, ever since the summer when the draw came out and everyone was talking about Toulouse coming to Galway. You could see it around the city, there was a real excitement.
"Maybe it was at the back of our minds, but once we get that one win, we can build it from there - and more wins will start coming. It is just - at the moment - the confidence levels are a bit low so we need to get a few tries and a victory."
With Gloucester having also lost both of their opening games O'Halloran believes the Galway outfit have every chance of ending their barren spell during the double header against the Cherry and Whites.
"I suppose Gloucester would be the weakest of the three in our group, so we would definitely be targeting them," he added.
"It really does give the players a boost when there is a big crowd there. The only thing now is, we have to start performing on the pitch or those attendances will start dropping again."
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