Our nearest gauge for what we might receive is the Raiders in 2011. They lost the top defensive player in Free Agency, a solid guard (though Brisiel is hands-down a bigger loss than Gallery), a good TE, and a solidly decent (though not every down) defensive player. They also lost a backup QB.

Oakland Raiders - 2011
Lost: Nnamdi Asomugha, Robert Gallery, Bruce Gradkowski, Zach Miller, Thomas Howard
Signed: Kevin Boss, Stephen Heyer

For this, the Raiders received a 3rd round compensatory (1st and only in the 3rd), a 4th round compensatory (2nd in the 4th), and a 5th round compensatory (1st in the 5th)

Houston Texans - 2012
Lost: Mario Williams, Mike Brisiel, Joel Dreesen, Jason Allen
Signed: Donnie Jones, Bradie James, Justin Forsett, Alan Ball

Looking at what picks we might get, I think Mario Williams will ensure that we get a third-round compensatory pick since he had a good year (10.5 sacks, 2 FF, 2 FR, 4 PD). It is likely to be the first second one awarded, behind the Colts, due to Peyton Manning (Manning was not a FA, he was cut [thanks Travis]). Brisiel started for the Raiders and Dreesen saw significant time with the Broncos (a starter in principle if not in name). Jason Allen didn't do much withthe Bengals (only played 4 games), but he was signed to a 2yr $8.2m contract with them, bigger than the 2yr $6.5m contract the Raiders' Howard got (also from the Bengals) in the previous year.

As for the players we received, the key is us getting a full-time defensive starter in Bradie James. This is what makes it hard to figure out what we'll get beyond the 3rd rounder for Mario Williams. There's a chance we get nothing else, but I think it more likely that we'll get something in the 5th or 6th round range. Splitting the difference, let's call it the last 5th round compensatory pick (last year there were 3 last year).

Sooo...

Pick 95 (33rd in the 3rd round)
Pick 170 (35th in the 5th round)*

* - assumes 8 compensatory picks are awarded for the 4th round like in 2012