Well TCWO seems to be a good place to get 1 ghz 266 FSB chips, I have gotten 3 from them, and all of them were AXIA. You can get them for $122 +$7 for shipping if you call them and mention you saw that price on pricewatch.
As for CPU coolers, it all depends on how much you want to spend, so let me know and I'll give you a recommendation. The best cooler out there is the Swiftech MC-462, but that will cost you $80. Also let me know if noise is an issue, and I will help recommend a fan for you.
As for northbridge cooling, it might help you get like 5 mhz more FSB speed, but your motherboard should already be able to do at least 150 mhz FSB already, so if its worth it is up to you.
Aaron