Path of Insallation File

I have created a project which has a file name 'appconfig'. During installation of that project (through exe) i wanted to search the appconfig file if exist (in the same folder where exe exist)then use that otherwise create a new one.
I am using Installer class for my custom installation where i define certain values during installation like database path nd all.. This claas called during installation which invokes a configuration form to configure all values . at this time when i search for that directory where exe exist i am unable to get so..
all i am getting through Directory.currentdirectory is c:/Windows/system32..

How do i get that path....from where installation initiated ?

Is there any property in Orca otherwise from which i can set patha to get that file

Please Help