Will having two antennae at the receiver give better reception?
Not really.  Wi-fi cards that support using two antennas generally have an internal switch that will select one antenna or the other.  The card will select whichever antenna has a better signal.  This is called diversity, and it is used to counter issues with channel fading.  Newer wifi cards can use both antennas at the same time.  This is called MIMO and under certain circumstances it can allow a 2x improvement in bandwidth.  In terms of range, diversity will allow the card to counter some forms of fading and can improve reception and reliability, but it will not increase the range unless you use a higher gain (more directional) antenna.