a tripod can be useful for this sort of thing and either lens should do but the 17 - 70 might serve you better
camera settings i would go for F8 - F11 , 100 iso and 4 - 8 second exposure
if you have a remote shutter release use that too but it won't do too much harm if you havn't
wide angle lenses are essential for large firework displays but setting a few fireworks of in the garden doesn't really need it