There are a couple of options if you need to pump up your suspension.
If the car is drivable or can be towed, a Mini specialist may be able to help out. The Mini Deluxe, Mini-K and Mini Coopers all have Hydrolastic suspension so most Mini specialists have the expertise and equipment although they are not always that enthusiastic about working on an 1100. Some may have a portable pump that can be hired out for a small charge, allowing you to do the work yourself.
However, if you want to do some serious work on the suspension you may prefer to make your own hand pump. Often I read where people have used a grease gun as a pump but most fail to explain exactly how. However, I did find a website which explained, with pictures, how to do it and although I am happy to report that I have successfully made and used a grease gun as a pump, the site has since disappeared.
The secret is thefitting on the end which is apparently called an "Air chuck" in Australia. This fitting allows you to securely attach the hose to the connection on the car and tighten it without releasing any fluid. Once attached, you then slowly screw down the tap on the top which presses in the valve releasing the pressurised fluid safely into the pump and not all over the engine bay...