Finding a companion for a 3 year old adult female

Question
A friend of mine has an adult female guinea pig that she no longer wants.  
The female had another female companion that died 6 months ago.  I would
really like to take this guinea pig on but would like to find a suitable
companion.  Is it safe/advisable to put a young female guinea pig with her or
is she likely to reject it. Or is it better to put 2 young female siblings with her.  
How can I find a suitable friend?
I have recently lost my male guinea pig - a fox got into the run and he died of
fright.  It was terribly upsetting.  He was less than a year old.  On poor advice,
I had housed him with a medium sized breed rabbit and although they got on
amicably, I feel they were both quite lonely.  I managed to get the fox off the
rabbit and save him.  He seems fine now - and has lots of contact with me
and my children.  I have another hutch in which I can house the guinea pigs.  
I love guinea pigs and would like to try again.

I would be grateful for your advice.

Answer
Hi Nicky

Firstly I am sorry to hear about the fox incident.

There is no reason why a young female would be rejected by the years old. Take a look at the link below for step by step guide on how to introduce them. As with all animals, there is always a small possibility that they just won't like each other.

Andy

http://www.diddly-di.fsnet.co.uk/The%20New%20Arrival-existing.htm