Computer compromised?

30 minutes before I have to go to work I click on my gmail icon. I see a big red banner saying that someone has logged into my account from Algeria. I was freaked out by then, and proceeded to change my password, probably not to something secure enough, but I changed it all the same. So I thought, "Fine, that should be the end of that." But I was wrong... I skim through my emails and see an email from Steam saying something about a password reset request. Now I know I did not do this. I see the ip in the email and it looks nothing like mine. So I search it up, and low and behold, I see that it is from Brazil. Now I am really freaked out and stressed.

I ran two MalwareBytes scans, and an avast scan, but nothing showed up. I am also scanning my mothers computer with the same method, as I have logged into her computer with my gmail account before.

What else can I do to make sure nothing happens to me and my precious files and info? And do you think someone already has a hold of my computer, or my moms?

Download autoruns, run it in safe mode, look for anything suspicious and disable it from running on startup.

Just because they entered your GMail account doesn't mean they've done anything whatsoever to your PC.
Your GMail account doesn't exist/run on your PC so someone entering it doesn't gain any access to your PC.

With knowledge of your GMail account they can go after other accounts without ever having any need of infecting your PC.

Take steps to secure anything that shared a password with your GMail account or could've been accessed or reset using your GMail account and you should be fine.

Ah yes. Someone accessed my e-mail from China. I changed my password, and I don't think they noticed anything besides my massive amount of college crap.

Don't worry about it.