First thing to think about is if you really need it. Note that not all businesses are required to have computer systems in place. The task required to be done is one of the factors to be considered when deciding whether to buy a computer or not. If you think that the business is still manageable with the trusty pen and paper, then you can forget the computer, this is pretty much the case with small businesses. If however, the tasks have increased in number and became more tedious, for example, during expansion, you definitely need to have a system to organize and manage everything more efficiently.
The next thing that you will to think about upon deciding to get a computer for your business is which one to get. This again depends on what you are going to do with it. If all you are going to do is make documents, manage account ledgers and all other paper works, you can get a general purpose machine. If, however, your business involves such specialized work, such as graphics design, photo and video editing or web based services, then you need to get one that is more suited, or you can upgrade you current machines.
Of course, you need to consider the cost of the computers before buying. However, with the recent trends in technology, entry level computers have become relatively cheap. If you need to go for specialized machines, it would be good to build one yourself, since buying specific parts is much less expensive than getting customized machines. You can also have the computers suited to your particular needs this way.
And of course you need to hire people to use them. For the easy tasks, such as transcription and document writing, all you need are people with basic computer skills. Choose those with relatively good typing skills to make the work faster. In other cases, you need to hire people which have a good deal of knowledge of using specific programs and hardware for special tasks. Remember also to hire technical personnel to maintain and repair your computers.