my sister has had this problem the last couple of days!
her fiances kid brought back a cat that was very disorientated and they think its blind as it just keeps walking into stuff.
They have 2 dogs that arent used to cats, and 3 people in the house are very very allergic to cats!
She phoned the local Cats protection League today and they said they dont have any spare boxs atm, and to call them back saturday!
I told her to take it to the vets, but she was worried she would have to pay, but as far as i know & from experience, if its not your cat, they dont charge you.
So she is taking it to the vets tomorrow :)