Welcome to TFP!
If you look in my signature line, you will see I have the same pool. Yes, you can put the large fittings on your pool. It is strongly suggested that you upgrade your pump/filter unit to at least the 2500 gph pump/filter. You will need a few items to do this, link below.
Complete upgrade package
Search around Amazon.com and other places, you may be able to find a lower price for the complete package.
Also highly recommended is an upgrade in filter media, such as Unicel C-5315 or Filbur FC-3752 filter cartridges. Much better than the Intex branded.
Installing the larger strainer ports -- suction and return fittings -- will require cutting the new holes in the liner. you can cut out the smaller ports, and add these in place. This will NOT hurt your liner!!