STEPS TO INSTALL SINHALA FONTS
1. First Download the Font file that I have attached
http://www.locallanguages.lk/sinhala_unicode_converters
2. Go to system/fonts/ from root explorer or which ever the file explorer that you use and it has to be enabled with super user
3. Just overwrite the file and restart the phone.
4. Sinhala rendering is now 100% .
Enjoy!!!!