Just wondering, what is the latest file number on your picture? I have only reached about 8k counts of my shutter, but never had considered changing the shutter as I only believe it'll break when it wants to break.
So, give no more thought about it, and continue shooting till it finally break! That may be many more years in future or touch wood, maybe tomorrow? If it does, Canon Service Center is at Harborfront, which is easily accessible by bus, mrt, or even taxi.
based on "http://www.the-digital-picture.com/Reviews/Canon-EOS-Rebel-T1i-500D-Digital-SLR-Camera-Review.aspx", shutter life for 500d is 100k.
assuming it was released in may 2009 and u got it since then till now that is approx. 2yrs, means that you shoot 137 pics per day. *faint*
There aren't many people who can change the timing belt of their car .. and I guess it's similar with photographers who can change camera shutter. If you don't exactly know what your are doing then Service Center is your best friend. But in contrast to timing belt there is no recommendation to change a shutter. Use it as long as it works, change when broken.
the is no certain limit that the shutter will fail, but just higher chances.
don't worry so much about it, hardly for casual shooters will shoot till shutter fail, even it is failed, you have all ready making full use of your camera, high time to write it off and just get a newer camera, probably is already Canon 800D or 900D.