I really want this ich to go away, is it okay to make the temp rise to 30 degrees celsius? And which one is more effective:methylne blue or aquarium salt?
Ich takes time to get rid of, be patient. All the methods are effective, if carried out correctly. Once you choose a method see it out until the end, the worse thing you can do is try and kill the ich using all methods at once, that will kill your fish.
As far as temps go it really depends on your fish, some can tolerate higher than others. All the higher temperature does is speed up the cycle of the ich, temperature alone won't kill the ich unless you go crazy high, but then your fish will die too. You can raise it up in slight increments, OBSERVE YOUR FISH, and be sure to increase surface agitation to increase oxygen levels.
Just give it time, you've had some good advice. Don't be too disheartened if you lose the odd fish, it happens with ich. But it's better to lose the odd fish than your whole stock.
Good luck, keep us posted of developments.