Just an FYI - if she placed before, not involving CPS...then that is no reason for CPS to be involved with her now.
She has to have a history of CPS involvement for her to be involved with them now...it would be in your best interest to find out what and why that is. If they are drug testing her, then I would bet that she is involved with CPS because the previous child was born addicted and/or exposed to drugs.
As for the process...Texas is S-L-O-W. You can find an attorney now, make sure you have all your ducks in a row...but Texas isn't going to finalize the adoption for at least a year. Once they do that, you'll need to update your China Homestudy...
Consider that China requires a year between kids...you need to make sure that you've got enough time...and that placement time counts...not just time from finalization.
Visit
Adoption Directory - Local Services Professional Agency Attorney Facilitator Adopt for a list of adoption attorneys and other professionals in Texas.