So, wait, you have a router which provides a connection via cellular data, but your PC just connects to the router via regular Ethernet?
In that case, as far as Mandriva's concerned, it's just a perfectly standard Ethernet connection. It doesn't matter at all to Mandriva and your laptop how the router ultimately handles the Internet connection - that's the router's problem. All your laptop cares about is talking to router, which is done as a standard ethernet connection.
If I read your post wrong and this is not actually your situation, please clarify :)
So, further: in no case will the purchased version of Mandriva work better than the One edition for networking. The things that are unique to the purchased version are commercial software, and there's no commercial hardware drivers included, so as far as hardware support goes, One and Powerpack are basically identical.
Free has slightly worse hardware support out of the box than One or Powerpack, simply because it only contains free software; it doesn't contain any non-free-but-redistributable software, like the NVIDIA and ATI graphics card drivers, or the firmware for Intel wireless adapters. These are included in One and Powerpack. You can add them to Free easily once you have an Internet connection, but they're not there out of the box.
2009 does work with some hardware that didn't work with 2008 Spring, but we really need some more details on exactly how your network is set up and what the problem is before we can be sure what it is you need. But definitely don't go out and buy a Powerpack, yet - it's not the answer to this problem.