Looking for non genuine Nissan remote control.

I have a Nissan Patrol late 2001 3.0 liter Turbo Diesel and the little Grey plastic remote control played up so I asked Nissan and they quoted me $19.60 for new battery. Result I walked out went to AAA batteries in Cairns and got same one for $4.50. It worked for a few days but has gone bung again I have tested battery and it is okay. Just a couple of questions

1 where can I get an after market remote control as Nissan want $150 for the remote and $100 to code it (stuff that)

2. How can I test to see if remote control is okay and if it is how do I re code it.

3. Does it have a separate fuse I have had a look but there are so many fuses relating to ignition but nothing to remote control which I would have thought there would be.

4. Where about's is the receiver for the remote control

The ignition key works okay so that is no worries.

Thanks peoples.