The definition of drapa is 'Fornnordisk hyllningsdikt med konstfull utformning" - i.e. an elaborate poem praising something, not that different from an ode perhaps, but the word carries a distinctly Old Norse or "viking" flavour.

When used as in your context, it is to be taken in a jocular and non-literal way - not too different from how you might refer disparagingly to a story you are telling that never seems to end like a 'saga' in English, or something you have written, as an 'epic'... which is probably the best option here, unless other context shows that the 'praise' part is important, in which case I don't know...

'Ode' would be a semantic fit, but sounds out of place and not very idiomatic.

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Note added at 9 hrs (2007-08-15 09:16:34 GMT)
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Reading through the context again, it's possible the author does not quite know what a 'drapa' means - he or she refers to (skrivit en drapa om eländet' ('written a 'drapa' about the(my?) misery') - hardly sounds like praise does it... so in case the author meant it to be negative but had misunderstood the actual meaning of 'drapa', perhaps 'lament' would be an option?