Thread starter, I'm sorry if I'll sound harsh, but I sincerely believe that you're the type of person who is secretly attracted to drama in your life. Subconsciously, you crave it. And when it's there, deep inside you, you revel at it despite the difficulties it brings along. This need for drama, whether we are aware of it or not, is a manifestation of one's need for attention. Just look at the way you phrased your post. It was all about you and your sufferings - not the child's, not your child's mother's, and not your current partner's. It's all about your feelings. It's all about you.
Again, I'm sorry if this sounds harsh, but I have to tell you this as a way of slapping your face - figuratively speaking - to wake you up and to remind you, if not make you realize, that everything - EVERYTHING - is in your favor.
So please, tama na muna ang drama, pare ko at mag-focus tayo sa kung ano ang totoo at kung bakit wala ka naman dapat problema.
Think of it this way: you're the point guard in a basketball game. Your team is up by 20 points. You have the ball. Then, all of a sudden, you walk out of the game.
Stupid, right?
That's how ridiculous your current idea is.
So the mother wants to deprive you of your right to see your child. Not a problem. File an action for Enforcement of Visitorial Rights Over a Minor before the Family Court where either you or the mother resides, or if there is no Family Court in any of those areas, before the Regional Trial Court.
The mother is about to hide the child? Add an application for a Writ of Preliminary Injunction with the action mentioned above to stop her from doing so.
The mother has already hidden the child? File for a Writ of Habeas Corpus before the same venue.
You are the natural father of the child. The Family Code is on your side. You will win.
Also, as Kikomaching1 stated, the mother cannot change the child's name without a court order. Before such an order can be awarded, publication of the application is required. During the period of publication, you can file your opposition to the change of name, and a full blown hearing will ensue where you can lay your arguments. You are the illegitimate father. Your surname was used in the birth certificate. RA No. 9255 is on your side. You will win.
With basic writing and research skills, you may not even need a lawyer for these actions. But if you don't feel comfortable about representing yourself and if the procedural requirements may seem too daunting for you, you can hire one. If you can't afford one, consult with the Public Attorney's Office in your area.
Now go on. Don't be stupid. You had the time to mope and dwell in your self pity, you should have the time to BE A MAN and make things right.