In that case, I think some of the the AK topcovers fit Galils. Since Galil topcovers are so expensive, I would recommend that route.
But anyways, remove the rear galil sights and put A2 rear sight onto the rail. You should still be able to use your front post, but would lose the rear night sight. Tennagalil could probably mod all this up for you as well as figure out a way to add/keep night sights on this setup if you wanted them. Regardless, the SA front post is a good addition.
The galil 300m peep sight when properly sighted in at 25 m/250m zero is basically a 275 yard zero. +/- 5" all the way to 325 yards.
In this chart the 37.5/275 yard zero is probably closest:
From here:
http://www.ar15.com/content/page.html?id=659
Point being, I think the Galil peeps are very effective for minute of man accuracy with substantially less opportunity for operator error sight adjustment/misadjustment resulting in misses... And just a sight flip switches to a 500 yard zero, which is ~ +20" at 300 yards with a 500 yard zero... .223/5.56's trajectory has about a 5 foot drop at 500 yards. Point being, the 500m peep and the 300m peep combined cover minute of man accuracy over the entire effective range of the 5.56 round, but again for MOA precision shooting/true marksmanship, neither is ideal.
Also, the A2 revised improved battlesight over at AR15 is a great read as well:
http://www.ar15.com/forums/t_3_18/328143_.html
And here's the santose improved battlesight zero referenced w/ 200 yard zero:
http://www.ar15.com/content/page.html?id=599