My first thought is that it's a baby blanket, so size isn't as big an issue as a garment.
At this point, there isn't anything you can do to change what's on you needles. If you wanted to start over to try for gauge, you'd need to use a larger needle.
If you just continue as you're going, your blanket will be 30 x about 33ish using the extra ball.
Another option is to continue as you're going and if you want it wider, you could pick up stitches along the edge and add a border, but that is a lot of stitches to pick up!
It's totally up to you and what you want your blanket to end up as.