Yeah I'd probably suggest better cooling cause it could easily go up 10 degrees while overclocking. Since you are at 333FSB I'd advise on just raising the FSB in your BIOS from 166 to 200 slowly an incrementally. You might not have to even raise your vcore for that. Keep in mind though when you start overclocking your CPU everything else gets overclocked too and you'll need to lock your AGP and PCI busses to AGP: 66MHz and PCI: 33MHz
Conclusion: To be safe yes I'd invest in a tad better cooling. If you don't have AS5 even something as small as that can offer 2, 3, maybe even 5, if you're really lucky ,degree decrease in temps.