I'm assuming your line looks like this?
ὁς θεον βωμους πατριδα τε ῥυομεθα
(Accents omitted because I'm not skilled enough to place them correctly.)
If I understood you correctly, the first four syllables are long-short-long-long:
- The first syllable is long by position, because the short omicron is followed by two consonants.
- The second syllable is short by nature.
- The third syllable is long by position, because the short omicron is followed by two consonants.
- The fourth syllable is long by nature.
Your transcription doesn't make it clear which "o"s are omicrons and which are omegas. But in this case it doesn't matter, since they're followed by multiple consonants anyway. (And *βομους isn't a word, while βωμους is.)
P.S. You might also find Latin.SE helpful for future classics questions.