To find your flightplan, we recommend you to use vroute. vRoute contains network information, as well as an extensive route database. They also offer a premium version which contains fuel calculations, links to charts around the world, export function to your FMC among other functions. vroute can be downloaded from the their website at vroute.net
An alternative to vroute is Simbrief.com, it is a free service (however you need a Navigraph subscription to activate the latest AIRAC), that finds your route, calculates fuel and much more.