Leaking Flex Pipe

Mechanic told me my flex pipe is leaking and needs to be replaced but they didn't have the part themselves. I checked at every auto parts store but none of them carry it. He said it's the flex pipe coming from the engine to the rest of the exhaust. I don't know where to look online, where can I order this thing?

I found this stillen exhaust part, it looks like it includes a flex pipe.
http://www.stillen.com/product.asp?id=STIHDR01&c=PE
If I buy this and install it will it replace my flex pipe? =\

http://cgi.ebay.com/ebaymotors/1996-2001-Nissan-Altima-2-4L-Engine-Exhaust-Flex-Pipe_W0QQcmdZViewItemQQcategoryZ33630QQihZ009QQite mZ190070942773QQrdZ1