You don't need a macro lens to take close shots, you just need a lens that is good at close focusing.
For your situation where you want a lens that is good for taking portraits and candid shots both indoors and out, I think the Tamron 28-75mm f/2.8 would be a natural choice, and in threads like this one it usually gets mentioned earlier than this. Great image quality, fast and constant aperture, flexibility of a zoom, and ideal focal lengths for portraits. And it won't break the bank since you can often find used copies for under $400 on eBay. And with it being a popular lens, you can always resell it and get almost all of your money back if for some reason you don't take to it. Just hold onto your 18-55mm for the occasional wide shot.
And since you specifically mentioned close pictures, I would point out that the 28-75mm will focus on an object that is just a few inches away from the front element. I wish my Sigma 50-150mm f/2.8 could do that!
The biggest drawback of the Tamron is that it does not have a silent autofocus motor. If that is important to you, then Sigma makes a competitor with HSM. But, of course, that means the Sigma costs much more, so it's a trade off. And from what I've read, the Tamron has better image quality and bokeh than the Sigma.
In case you haven't already stumbled onto it, here's a thread where I posted a bunch of pictures that I've taken of my children and their cousins with the 28-75mm on my (white) Pentax K-x:
https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/145599-tamron-...lots-pics.html
Good luck, and let us know what you end up buying!