Awesome that you rescued her.
I notice you didn't specify what type of Macaw you are looking for.
Have you called Varietees bird shop in Valley Park? I dk how often they have large birds, but I do know they have parrots there.
Whatever you do, make sure you get a fully weaned baby-- it is so important...some people perpetuate a myth that hand-feeding will improve your bond, but this is false. A fully weaned baby will generally be happier, healthier and more well-adjusted in the long-run.
When deciding on the sex of your future bird and a 2nd bird in general, here are some things to consider (in case you haven't):
It's not the best idea to get a bird for your bird (unless you personally want a 2nd bird for yourself). Getting a bird for a bird is like picking a friend (or girlfriend/boyfriend) for a teenage kid (doesn't always work).
If you get a 2nd bird, there is a chance they will not get along...and in that case, you may need 4 hours with one out of the cage and then another 4 hours with the other out (or something like that---separate interaction time). There could be some jealousy issues with the introduction of a new bird etc. If they do get along, that can make bonding with a human a more difficult process (due to their tendency to pick a single bird or person). It could also change the relationship with your current bird (in addition to potentially complicating the bonding process with the new one). That is just something to consider if you haven't already.
I am not a total Macaw expert- and I know you didn't ask for my advice, but I wanted to comment on your idea about a male and female- once sexually mature, if they get along, they may mate if out together at the same time etc (whether or not you are ready and whether or not you want them too)---You may also deal with some pretty raging hormones and behavioral issues that arise from housing 2 birds of the opposite sex.
This can get complicated though because raising babies is NOT a simple or cheap task (I used to think I could hand-raise a chick, I mean how hard could it be?---It's way harder than I thought).
There can be all sorts of stuff that goes wrong, where the human ends up having to intervene. Unless you have apprenticed under a breeder, I wouldn't try it. Plus, you would also need separate cages for all of the babies once they grew up or you would have in-breeding issues/genetic problems.
If they DO get along and you decide against breeding them, then you will still need separate interaction time (4 and 4 ), and they may not like that--so just keep all of these things in mind and read the links below before deciding on a male...Also- If the male's presence is a hormonal trigger for your current bird, she could end up laying eggs (even if they never mate) and that comes with its own health risks for the female, including egg-binding, prolapse etc.
Here are some links to consider:
http://www.parrotforums.com/breeding-raising-parrots/54987-before-i-start-breed.html
http://www.parrotforums.com/breeding-raising-parrots/74363-so-you-bought-unweaned-baby.html
https://hari.ca/hari/research-facil...cine-pediatrics-housing-feeding-baby-parrots/
