This extension helps you to create upload fields to your server and database so that you can work with the files.
If you want to validate file extensions you should get Form Builder, which can do that for you. You can create forms using this extension directly with validations applied, but you can also apply your own validations to a form that you have created by hand coding or using Dreamweaver.
Sending the uploaded file as an attachment to an email you will need Universal Email, which is an extension that helps you with sending out emails.
We do not have an extension that will limit the file size of an uploaded file.