What's the problem with that change? Your rating is not a single number, it's a normal distribution with mean and deviation. The number you see is the lower 3 sigma percentile: (you have a 99.7 % probability to play at least as good as displayed)
(they can't spell deviation in the image)
mean = expected skill in a game (1000 in the picture above)
deviation = average deviation from the expected skill in a game (20 in picture above, in FAF about 100 to 200)
displayed rating = 3 sigma percentile = mean - 3 * deviation = 940 in above image
If you win a game against a better oponent your mean will increase, but your deviation will get bigger, (the system is more uncertain of your skill) therefore reducing your rating dramatically which results in cancelling out the gain in mean (therefore just +3). Just keep playing, the bigger your deviation the easier it is for the mean to adjust, if you keep a consistent skill level your deviation will lower again therefore getting certain that you can play at a higher skill level and increasing the number shown.
Developer, currently working on ICE adapter, Java Client (downlords's client), java api/server.