I too have a role with multiple responsibilities, although I am thankfully doing them all in one office. Here's what I'm in charge of:
-Gift processing & acknowledgements (around 300 gifts/month)
-Reporting
-Database management
-Two major fundraising events (February and July), one donor recognition event
-Grants research
-Employee giving (annual campaign)
-some collateral production
It's definitely hard at times to balance all of these equally important duties. I've learned how to balance it all for the most part, but sometimes balance isn't a realistic expectation. Here's an article I've found helpful:
www.columbia.edu/itc/hs/pubhealth/isett/...ng%20your%20boss.pdf
You certainly can't change the amount of responsibility you have, but you can work with your bosses to make sure you're maximizing your abilities and performing the way you're expected to. If you've been told that gift processing is a priority, make that happen the way you need it to. Figure out how your other duties fit under gift processing, and ask what deadlines are. I've worked with plenty of individuals who think out loud, and it's easy to perceive their ideas as tasks that need to get done. You might believe that something is absolutely urgent, when in reality it is farther down on the priority list. Asking questions brings out the priority level. It does not hurt to ask for due dates on projects or tasks, and clarify any assumptions you are making regarding the tasks at hand.