You can do an inplace upgrade to 4.1.4 on your current BES version. Make sure to backup your database first. Depending on how many users you have, you may want to do this in the off hours as to not cause noticeable downtime for the users. Typically the upgrade takes 15-20 minutes if you take your time, and again the amount of users can make a difference as well.
If you have more than 200 users use the following guide: BlackBerry Search Results
If not just backup the database and run the installer, it should be pretty straight forward.
The only thing that might throw you for a loop is the upgrade options. You have BlackBerry Enterprise Server and Components and BlackBerry Enterprise Server with MDS Services and Components.
MDS Services(MDSS) is a way for you publish your own custom developed BlackBerry applications that your users can browse on their handheld and download. If you don't think you will ever use that option just select BlackBerry Enterprise Server and Components and ther est will be pretty much click Next til it's finished.
Let us know if you have any more questions.