don't do any thing in haste. first of all, do what maaya767 has suggested. he has also mentioned:
'oil sump where the filter is located'
most probably it will solve your problem. if it doesn't, then:
get a compression test
get all the engine seals checked
get the valve seals checked
look for any other oil leakage, clean the engine, look for leaks, inspect the area where you park your car.
i won't recommend changing the assembly, the biggest problem that would arise is that if you get a new assembly, you get a new engine number, which would then be changed in the car documents and it would create a problem when you'd want to sale this car. secondly, getting a new assembly doesn't mean that you are getting a 'new' assembly. if everything fails, get your engine checked for where the fault lies and get that work done using quality replacement parts from authorized honda outlets.