You would find that re-applying would be easier, instead of appealing which would take 6 months or more..Besides, the visa fee is not that much anyway. Like what the others said above, if the ECO would still not be convinced that you'd return to the Philippines, even the appeal won't be successful. Having properties (like house or land titles), a stable job, bank accounts, etc. would help even though it's not a guarantee. Make sure to supply everything that would make them believe you would return to the Philippines. Even if your sister would supply all the help available on her part, your proof of returning is the one that would matter most, not her's.