Urgent headset help needed

Hi all,
Today I went to replace the headset on my giant, all was going well until I tried to free the lower bearing, the bearing has rusted and welded itself in, the lower part of the sealed bearing has split off along with the ball bearings leaving the top part stuck in place. I tried to hit it out with a punch from the top opening of the frame but it is flush with the inside of the frame so you cannot get any purchase, I also tried drilling it but the drill bit didn't even make a scratch. I was going to try heating it with a blow torch but didn't want to risk damaging the frame.
Has anyone else had this problem or got any ideas what I can try next?
Any help appreciated. Thanks. Gaz

soak soak soak in gt 85 or eqivilent for at least a few days. Use a punch or a chisel from the bottom to try to at least get it moving or see if you can jar it loose. Possibly use the blowtorch only on the inside of the headtube to minimise frame damage but you are always gonna risk damaging things a bit when freeing seized parts. Or depending on how the race surface is and how sealed the bearings are dismantle a new one ad bodge it back together with the old one though that is less than ideal. One last though it use something that can wedge against the race from the inside, think like a quill stem, and see if you can convince it to move that way.

Hi all,
Thanks to your advice all is now sorted! I managed to remove it using a combination of all the tips, it went something like this. Whilst I was waiting for the ice cubes to freeze (badmanlongtime) I soaked the headset in release spray, after snapping the tips off 3 screwdrivers I decided to get the dremel out (thuekr), after cutting about 1/4 inch worth of little slots I managed to break them off and with it structurally weakened it finally came free :-)
So, thanks to your help all is good! Oh, and if your thinking he didn't use badmanlongtimes ice cubes.... They're now in the G&T I'm supping whilst writing this.
Once again. Cheers!