Ouch

The house needs to be vacuumed. The cats are shedding hairs, it's April, it's getting warmer... all to be expected.
Only one problem though: the dustbag in our vacuum cleaner is full. The thing is sputtering and smelling like... dust whenever you hit the "on" button.
And it's a new vacuum, we bought it with the bag inside and I just had to plug it in and have fun with it (as much fun as one can have while vacuuming, but I'm easily amused). Now though... I can't find the manual and I haven't got a clue how to replace the bag. No fresh bag = no vacuuming + three cats shedding hair = ...

Help.