Those needles can be purchased from Sudco International
http://www.sudco.com/
What size is your carb? Seems some guys are having better luck with the 36mm carb.
Also it never hurts to e-mail JD Jetting or RB Designs for help/suggestions.
JD Jetting has great prices on slides and complete replacement 38mm PWK Airstriker carbs. Not sure he has the 36mm available but it never hurts to ask.