Is your board a 5V or 3.3V output?
Either way, you need to feed it to the appropriate 5V or 3.3V pin on the Arduino, not the barrel plug (what you've labelled RAW, actually labeled Vin on the arduino). This will bypass the onboard linear regulator. Additionally, you should use a schottky (Low forward voltage) diode from your 5V or 3.3V to the VIN pin to avoid a possibly nasty inbalance.
The reason for the above is because the Vin (Barrel) input is designed to be 7-12V, and doesn't work well with less. And if you are stepping a 3.7V battery up that high, you are going to then burn the energy off anyways using the linear regulator. Since you are already using a regulator, you can skip using the linear regulator.
Also, my experience with the LiPo Chargers are that they tend to drain the battery when not charging it. Do you have a way to disconnect it? Also, Sparkfun sells a all-in-one Charger/Step-up board for 3.7V batteries that they sell.