1) Is it possible to Use the Entry.xls as frontend for MySql DB? (because the UserForm which I have created is designer one and involved lots of coding with a 2 years learning process, i'm a marketing Person not a heard core programmer.)
Yes, but it's a bit faffy as you need to install 3rd party stuff on each machine that uses your workbook, windows doesn't natively have a driver for accessing MySQL.

if the answer is yes then
i) Can I make it a browser based and a web application latter on?
No, you can't, this will need re-writing in an appropriate web language - since you're using XAMPP, then PHP is the most likely.
ii) is it possible to make it a Multi-User program?
Yes, web applications are multi-user by default. That said, there's no reason an Excel workbook can't be multi-user, each user has a copy of the workbook and uses it to access the MySQL server.

More importantly than the above however, is a proper understanding of relational database structure - the description of your workbook doesn't sound normalized so you will need to completely restructure your data to make it into a format you can work with in a relational manner. I'd start with reading up on relational database design principles and take it from there.

You may find it easier learning databases with Access and then migrate to MySQL as Access has a GUI, MySQL doesn't