Missy, I know what your are going through. After wanting kids for so long, here you have TWO! God is so funny sometimes!

I have to tell you that it will be hard. Everything you are used to right now will change. Just being able to get away for a nice dinner with your dh will no longer be easy. You have probably had a little taste of that with the little girl you have now. When they are totally your own after the adoption, then there is no falling back on the gaps between foster kids. The other thing I might add is that parenthood never ends. You never get that gold watch for the job. My kids are 33 and 35 and one of them still is a pip who needs to remember all that he was taught growing up. I can't explain why they turned out the way they did.
Having said all that, I'd say go for it. Having two in diapers won't be easy, but plenty of moms raise kids close in age and manage just fine. What does your husband think. Since this is involving him just as much as the dad, he should have 50% say in the decision.
And my final piece of advice, no matter if you end up with one or two children--enjoy motherhood and don't get too uptight about the small stuff. Enjoy drippy ice cream cones, don't worry if they don't finish their dinner, and try to have lots of fun doing stuff together. BUT--- don't depend on your child or children to make you happy. You might find some things about having kids that make you happy, but (1) the burden of "making you happy" is too much for any kid, and (2) they will always let you down anyway. Find your happiness outside of your children and just enjoy them for who they are and the experiences they bring into your life.
End of thoughts!!
We went on a rose trip today, down to Vero Beach. We saw 3 lovely rose gardens at 3 different homes. The last one the people had 140 rose bushes, all in profuse bloom--just covered with flowers--and no insects or blackspot. It was a breathtaking yard.
A fun trip.
Now we are all sleepy from the sun and I will probably take a nap really soon.