First of all, let me know if the package in testing works for you and I'll move it to regular extra repo.
For your question...
If your package had a number of bits and pieces as dependencies you would only want to remove the ones that you had to install to get the package to work, and not what was installed already.
For each item you want removed do this.
removepkg PKGNAME (at the command-line as root)
You may need to reinstall the gslapt version after you are done.
You can see a history of what you installed in a text file at ... /var/log/pkgtools
If it's recent it will be at the bottom.
You could also search it out with grep and have grep display the 5 lines before it with this.
grep -B 5 PKGNAME /var/log/pkgtools