I know the RPi needs a 700 mA MicroUSB charger, but can it handle a greater amp, namely 2.1amp?
there is nothing to handle, as the rpi will not drain more power than it consumes. if you intend to power something hungry from the rpi's usb ports (1.1A max) you may actually need a supply with some reserves. in addition, the board has a polyfuse that should prevent damage to the board on overvoltage conditions.
the rpi wiki has in-depth info on this topic.
The amp is the maximum current a charger can supply, not the amount drawn by the board. It does not make a difference if the board does not use all 2.1 amps, however it will make a difference if the board draws more than the charger can supply. And the pi can use more than the 700mA, say if you plug in stuff that draws on USB power, therefor more amps are only a good thing.
A 2.1 ampere power supply would be just perfect for your Pi! I am using a 2.1 amp power supply and it works just fine. Having more amperage could solve some power supply issues too, such as if you are using a non-powered USB hub, it could help out! So you don't need to worry about extra amperage, since any extra amps are great! Also if you're wondering about the voltage limits for power supplies for the RPi are 5.25V to 4.75V. So in conclusion, the more amperage, the better!