I am trying to figure this out, but online searches don't seem to be helping. In particular what I'm looking for is something like "In exchange for helping you, please help me" or put more simply "In return for X, Y." To be more precise, used in an actual sentence: "In exchange for me helping you with your English, please help me with my Japanese."
As has been noted in the comments, 代わり【かわり】に is the construction you are looking for.
When referring to discrete objects, it usually takes the following format:
e.g. このリンゴの代わりに何をくれる？"What will you give me for this apple?"
In the case of your request, there are a couple of other ways it can be phrased to achieve a more natural feeling:
I think the most common way to express "In exchange for helping you, please help me" is simply
though this of course doesn't explicitly include "in exchange", much like the English phrase "I'll do this, so please do that"