Jobbridge doesn't affect your entitlement to Rent Supplement - the additional €50 payment is treated as additional household income and will be disregarded when calculating any entitlement to Rent Supplement.
Depending on where you live, Rent Supplement may be dealt with by mail rather than in person - some areas of Dublin, Wicklow and Kildare deal with Rent Supplement applications by mail.
As there can be backlogs in processing claims, you should apply as soon as possible.