It seems that you are trying to install a binary RPM that was built for a different version of Linux.
It is quite possible that even if you satisfy the dependencies that RPM is complaining about that the resulting program still will not install or work correctly. RPM-based Linuxes are not mutually compatible in all respects. Python is a particular area of incompatibility because it is so widely used in a Red Hat-derived system like CentOS. Because of this, trying to upgrade or install a parallel version of Python to satisfy the dependencies is likely to cause a lot of other problems and still may not solve all of your RPM compatibility problems.
Instead, it will probably work out much better in the end for you to build the RPM from source, if at all possible. Ideally, from an SRPM. It would only be impossible if the package provider does not provide any form of source code or the package absolutely requires Python 2.5 and will not run on Python 2.4.
If you can get an SRPM, the rebuild process may be as simple as:
# rpmbuild --rebuild name-of-package.version.src.rpm
The advantage of that is that the resulting binary RPM is built against the libraries on your system, so that if it builds, it is almost guaranteed to work.