Stair gate(desperately) (Droylsden M18)

Hi there I'm really wondering if anyone can really help me out if just rescued a dog due to lack of care but I'm desperate for a gate to keep the dog from getting out as soon as you open a door and expesionally the front door he tries to get out and I'm scared he is strong and has great chance of getting out the door and won't catch him or wouldnt come back and I really don't want that I just want to give him a save and loving home so a gate would so really help dramatically I would be so overwhelmed if someone could help and it would be great if not to far away as I don't have transport but I could use bike from gorton and strap it to my back that how much I want to make things better for the dog he hasn't had a good life till now please message back many thanks