Can we use Debian armhf .deb newer packages instead of Rapbian official repository packages?
First of all update your Raspbian operating system version to get newer packages.
The general answer is no, unless you know exactly what are you doing.
Apparently there are different types of packages:
Debian armel and
Debian armhf. The formers are not compatible. The latters should be compatible but there might be differences in compilation or mixed systems. Finally Architecture independent ("arch all") packages are compatible between Debian and Raspbian. Reporting from here:
The short answer is if you don't know what you are doing you should not mix them. For the long answer read on.
Debian armel packages use the soft float ABI which is incompatible with the hard float ABI used by Raspbian. In theory it should be possible to install Debian armel packages in parallel with Raspbian packages using multiarch. However multiarch setups conflict with a hack we had to make to support the videocore libraries and there are other potential issues too. As such we don't currently recommend or support multiarch configurations with Debian armel and Raspbian armhf.
Debian armhf packages should be compatible with Raspbian packages but a system with such a mixture WILL NOT RUN ON THE PI. Furthermore there may be corner cases where libraries build slightly differently on Raspbian. Such mixed systems can be useful for development (they were used heavily in the process of creating Raspbian) but are not recommended for general use.
Architecture independent ("arch all") packages are compatible between Debian and Raspbian. Source packages should in general be compatible though some may need modification to adjust compiler settings (most Debian packages just use the compiler defaults but some use their own settings for various reasons). A test script for testing packages for armv7 contamination is available at http://pastebin.com/BtSdvrXM but the script is not perfect and can suffer from both false positives and false negatives