the cheapest way to get into the 13's with what you got is ls nitrous but you wont have the on tap power of turbo without having to refill open the bottle and what not all the time.
An ls swap with a home made turbo set up could be wicked and def get you into the 12's and not cost you an arm an a leg if you research what it takes to actually turbo your honda. Read read read
then check out homemadeturbo.com for some example of budget setups that rock
also, if you still have the stock d16z6 you could boost that and get into the 13's with a thought out setup with a good tune.
Beerbongskickass on here, hmt, ht has a stock ex with full interior and a stock d16z6 running mid 12's because he has a quality setup and a good tune. Which is a helluva lot better than a slapped together lsvtec and a crappy turbo "kit" running an fmu and struggling to hit low 13's