Since it’s kitten season, you may very well wind up with a companion for your original cat, or simply give in to those appealing photos all over the net and adopt a stray or an older cat.
Please think everything through beforehand, and I’d like to recommend you keep your new pet cat indoors all the time, unless it has a cat-fenced area or outdoor catio. There are just too many hazards outside in the modern world for a small cat to survive the ‘great outdoors’ for very long.
Here’s a great article by cat behaviorist Marilyn Kreiger, from ‘Catster’ online magazine about persuading a formerly outdoor cat to happily settle down indoors. Read it here: http://www.catster.com/lifestyle/cat-behavior-tips-bring-an-outdoor-cat-indoors-for-good
And now you can simply enjoy many years together! Purrfect!