overall db solution anyone?

I am working for a company is experiencing severe growing pains. We are currently using FileMaker as the db to service the accounting and sales departments and using MySQL for the web back-end. As we have ecommerce capabilities, we are saddled with exchanging data collected on and served to the web site (in online sales, user data, product information,etc.) with the other depts. As this is already untenable and cannot scale any further, we are looking to use one integrated database system to hold all the data we need. As we also need to completely redesign the db to scale to the current and soon-to-be size of the company, we are certain there must be a product or service out there that has somewhat ready-made designs or templates for a mid-size company like ours with the ability to service sales, marketing, web, accounting, etc., hopefully with some extensibility so that we can direct it as it and the company grows. The reason I ask this here is that our Web site has been built almost completely in PHP and we are very happy with it. Therefore we prefer to find a product that can work with it otherwise we would need to rebuild the entire site. I know Oracle is one popular solution but considering the price of licensing, running and administering Oracle, we really dread having to go that route. Ditto for using SQLServer, SiteServer, ASP and a Microsoft solution. Are there products or environments that PHP can work with other than MySQL that have the above capabilities or are we pretty much stuck with looking into Oracle and/or MS? We are not looking for OpenSource solutions necessarily, just something that is not as closed end and expensive as these two. Maybe we are a bit naive.... Feel free to respond off-line, if you prefer. Thanks!