Insulation, Radiant and Vapor Barriers - Attic Insulation-What Type ??

OK.... Here's the million dollar question. I currently have a single home with a pitch shingled roof. Theirs approx. 4 inches of blown-in insulation in my attic. But theirs no vapor barrier. So.... I get a some moisture up on the particle-board sheathing of my roof. I have put in a gable fan and that helps with ventilation, but I feel I still need a vapor barrier. I maybe losing heat as it passes through to the attic.
QUESTION: I'm considering putting in a Kraft-Faced insulation down first (R-11, 23 inches wide) on the floor between the 24 inch joists and then throw the old blown-in insulation over the rolled insulation. Is that OK to layer two types of insulation ??
I figure I would then have a vapor barrier with the rolled insulation and then some additional R-value with the few inches of blown-in.
Please help with this issue ???

Rather than go through all of that with removing and replacing your existing blown-in insulation, why don't you just roll a kraft faced R-19 or R-25 over the top of it? You'll do a lot less work, have better insulation (or at least a higher "R" value), have your vapor barrier, all for very few dollars more than the R-13 is going to cost you.

Your absolutely right, Lefty. but here's the catch.... I can get Kraft-Faced R-11 and or R-13 for about 40-50% off the going price. My current price for Kraft-Face R-11, 23inches wide is $18.00 a bag. It goes for about $23.00 at the local Home Depot. Pulling aside the blown-in is a bit of work but what the heck, it'll take all day. My main concern is that I'm able to mix match the two types of insulation. Does it sound like that's ok???

Mixing the different types of insulation is not a problem. It's done thousands of times everyday.

Thanks again, Lefty, Two last questions. I calculated the left portion of my attic which I'm to insulate. It's 432 sqft. (24x18)
1ST. QUESTION: Putting down the wide (24") R-11 Kraft Face. Does that need to be stapled to the 2x4 flooring? Or can it just be laid down between the 2x4's on the floor to create my vapor barrier?
2ND. QUESTION: Should I also insulate the side walls with the R-11?? This would be the Gable Vent Sides - East and West side of the Home. All there is on those walls is the thin 1/4" or 1/2" house wrap sheathing - kinda silver faced stuff.