Wireless N maximum possible data rate is 600 Mbps. That's 75 MB/sec. PCI data rate is at least 133 MB/sec. So, PCI bus is most probably not your bottleneck.
Regarding the wireless range, chipset and antenna play a major role, not the connection/bus technology. So a better card with an external antenna connector, with a better antenna, will have a longer range. PCI or PCIe, it's not important.
First figure out where your bottleneck is, I suspect it's your Internet connection (from your router to the Internet), and not a wireless link from your computer to the router.
1> First figure out where your bottleneck is, I suspect it's your Internet connection Or from the ISP in regards to the total speed. As for range, that's probably being limited by the power of the card (check the settings; you may be running in reduced power and can configure it to use more), not to mention walls and such. In short, haimg is correct; the bus connector of the card plays pretty much zero role for a network card (at least a wireless one; a wired one connected to a gigabit intranet may matter). – Synetech – 2012-06-14T19:12:19.407
3while pci is capable of being 64 bit and double speed (66) MHz, these varieties are very rarely seen outside of servers. – Mokubai – 2012-06-14T19:40:27.827