How do I make my windows partition show up at boot time without holding option?
Unfortunately there is no default boot loader option built-in to Macs. Your best bet is going with a custom bootloader like rEFInd (see http://www.rodsbooks.com/refind/ for download and instructions). Normally I don't just include a link and call it a day but obviously I'm not going to have an alternative download available for someone else's program... and if the program is still available to download, the instructions will be right there with it at the program's site.

If after downloading, reading the documentation, and attempting the setup for this you still have issues, I recommend putting up a fresh question specific to that.

Aside from that, there are no options without getting very low level into nvram settings that you do NOT want to mess with... or at the very least I will not help someone mess with.

Good luck!