hi there,
i feel your pain!! i had to work so much harder to sleep-train #2 - so much harder with a 2 year old running around.
it took about 6 weeks before i saw any real effects on extending his naps & independent soothing. he was about 16 weeks old when it really started to take effect, and has been improving ever since.
so, to answer your question, yes, it will get better - just keep up all the hard work!
HTH