ph-ndr good if your friend is coming too - but to be specific - from what you've said (assuming your friend also travels J) you'll have 95kg!
2 x J = 80kg
1 x gold member =
15kg
=95kg
Also remember that no single item can weigh more than 32kg (see link below)
http://www.qatarairways.com/th/en/baggage.page