Is it possible to increase Galactic effectiveness in Mass Effect 3 by editing the coalesced.bin? If it is, how can I do this?
Not directly, but you can in fact edit the value of earned resources to be worth 10k etc.
Grab the Coalesced.bin editor here - http://wenchy.net/me3-coalesced-utility/
bioui - sfxgame - sfxgawassetshandler - allassets
Pick something you haven't unlocked and go to the Type=GAWAssetType_Military items; set StartingStrength to a large number like 5000 or whatever.
All you really need is 10k, since 5k is the max needed and readiness can't dip below 50%. Just so you know, I haven't done this myself but know others have. I'm on the 360 and it's pretty trivial to get 5 to 6k.
You can change your readiness to 100% by overwriting your local profile. This will reset your achievements. You will also need to manually load your save if you were in the middle of a game using "Load game" instead of "Resume", but after you've done that "Resume" will work as normal. This archive (alternate download) contains the file and instructions on where to place it.