oic. I thought the filters were in the attic. Well tommorrow when you get up I recommend you get that 2.5 down and put them in it. It's only temporary...shouldn't be more than 15-20 minutes to half drain your ten then pour some water through your filter then drain another 40% refill the whole thing cut on the filter and heater. Then you can start the acclimatisation process. Keep in mind you will still have a mini cycle going on.
EDIT: btw I'd use 50to25 mix of tap and tank water when I fill the 2.5 then I'd put the fish in and after you refill the ten I'd add the other 25% of tap water. Then I'd drain and fill the 2.5 until I had completed the acclimatisation process. Man this is complex. You said you didn't have any suitable bags didn't you...