Database Creation

Currently, I have a database which stores client information but this has been done in Access (by me) and Access is system hungry and therefore slowing my laptop down.

What I am looking for is either a standalone program or one which I can access from my web hosting server. What I also need is to be able to be able to add data fields if I find that I need another piece of information to the structure of it.

I run an accountancy practice so what I would like to see is a list of all the clients where I can double click and it displays all the client information in a form or something. I also need the facility of adding new clients, deleting, a report designer (or some kind) for extracting data (such as names and addresses for mail merge). A dating system would also be needed and linked to a task system which I would like displayed on the client list page which shows that if a return is due, it picks it up from the client data, displays the task and due date.

There is also future potential for this product.