with your usb to ttl adapter installed and working..
gnd->gnd
5V->5V
tx->rx
rx->tx
..hold reset down until compile is finished.. release as soon as u see 'upload'
I do this 'all the time' using this adapter
http://www.ebay.com/itm/USB-To-RS232-TTL-Auto-Converter-Module-Converter-Adapter-For-Arduino-S9-hv2n-/301019253456?pt=LH_DefaultDomain_2&hash=item4616254ad0