Nedd to check with Asrock first to confirm Pentium E6300 is supported, you old board is quite too old and might not support new processor
And if it supports, then performance should be much better than Celeron D processor
That motherboard is not worthy of an upgrade. I say, wait and buy a new computer.
Accoring to ASRock, you could have a 65nm Core2 e.g. E6700 or Q6600.
The Wolfdale is 45nm so isn't supported, it might work however, you jsut need to try in that case.
They say that you have to overclock the FSB to support the 1066 FSB chips and you need DDR400 RAM for it to work.
It's upto you to decide if it's worth it.