Online database design, creation and hosting

We are looking into having a customer database created that is hosted online so multiple users can use it remotely at the same time. It needs to capture customer data including the usual contact details along with other data such as where they found us, which service they are interested in, which member of staff dealt with the enquiry, how we were contacted etc etc...
As well as this, we would require the system to track whether the enquiry had been actioned, along with a pop-up reminder, similar to the one that Outlook uses. So if we were to set the system to pop-up a reminder to follow up an enquiry after four days for example, it would do this automatically after the fourth day from when the contact was created.
The system should also have a quoting system that creates quotes as files that can be then emailed to the client via a single button action if an email address has been entered.
All this needs to delivered via an intuitive GUI that looks cool and fresh.
Any other features you think would be useful would be welcomed!
You will also need to host this for us please via a secure login.