The post above links to gravy separators. I recommend the Oxo - that plug makes it better than others.

This is one of the most important kitchen tools, and nobody mentions it. I use mine constantly for de-fatting soup stock and other potions. You can just ignore all those instructions about trying to skim off the fat or chilling in the fridge to solidify the fat.

Since I'm usually separating a lot more than the 4 cups it holds, I pour 2/3 off, shove in the plug and refill for the next batch - no fat gets through. That gray strainer top it comes with, on the other hand, is totally useless in my opinion. I
use a regular wire strainer, much better. The plug should not be stored in the spout as it will become less effective.

The only flaw is that it comes with no easy way to clean the spout thoroughly - and I'm a real stickler on thorough cleaning, so I bought a cheap bulb baster that came with a brush and use that on the spout.

For refrigeration, I'd keep it down under 7 days. The failure mode would be mold.

As for freezing, I really don't know. Sounds like it'd work, but I don't know the effect on the gel, so I put a slice up in the freeze to test it. I'll report the results.

Freeze and thaw cycle was successful - possibly there was very slight degradation of texture but not serious. Apparently pig gelatin can stand freezing just fine.