If you know what lipo battery you like to have, it's a good idea to look around on ebay.
You can buy them and also the lipo loaders for a good price...
About the voltage regulator, i guess you need that one for your arduino, so it isn't fried.
To load a lipo you need a charger which is capable to load the amount of cells of your lipo, a one, two or three cell etc.
Also there are chargers available that can load all these kind of lipo'shttp://www.ebay.com/sch/i.html?_nkw=lipo&_dlg=1&_ds=1&LH_PrefLoc=2&LH_BIN=1&LH_FS=1