Based on the PSU sizing calculator at http://www.extreme.outervision.com/PSUEngine
and using my arbitrary assumptions about drives and fans, plus allowing for 10% capacitor aging, a 337W PSU is needed. If I increase that to 25% aging, 376W is needed. So if your machine hasn't been ridden too hard, it ought to work, but you may be close to the limit. When you can, a PSU replacement might be appropriate, just to be safe.