They are called Philips "Easy-fit" speaker connectors. They are a proprietary feature and a p.i.t.a. ;)
Here's an article on how to replace them.
And here's a listing for replacement parts on eBay.
Hope that helps!
You can use wireless repeaters to increase quality over such distances. You need to have 2 pairs of Receiver and transmitter. Connect the Output of one Receiver with the Input of the Second transmitter. Also gain the Signal a bit on the second transmitter. Use different frequencies for each pair.