valve seal prob, burning oil&fuel

[terror032.5]

does anyone know how big of a job that could be? i did a compression test and only one of my plugs compressions was low at 124 and others were 143lbs, at first i thought it was a piston ring & then a head gasket cause it was burning oil but it was also running super rich and burning fuel just as much as the oil. so does anyone know how long that kind of a job could take? and would i need to take my head in to get machined for any possible warp..?

2003 alti 2.5s