WN1000RP vs WN3000RP

I doubt you're going to see much of an improvement in range and as for performance - well - if performance is an issue, extenders should not even be considered. Let me explain ... WiFi is what we call half duplex - it can receive and it can transmit, but not at the same time - for a wireless extender to work, it must first receive the data, and then switch modes, and re-transmit the data - ignoring the switching times for convenience, you can see that just adding an extender will reduce throughput by at least 50%. Now - let's put this in proper perspective... Let's say you have cable internet, good for 15 mb/s down - your extender will reduce that to 7.5 mb/s - you're taking quite a hit to achieve that additional range. What do you use your network for - if you're into media streaming, between devices on the local LAN, moving to an N300 potentially offers double the performance (that you're getting now), but, if, like many people, you're just surfing, in which case the internet connection is the limiting factor - you're unlikely to notice the change.