Square as hell parlay but I'm sure soccer isn't your strongest sport.
It will more than likely hit but with the FA cup you never know, assuming barcelona wins (they should comfortably, although it's a derby), that will leave you with the Arsenal game which is on tomorrow.
FA cup is full of surprises and no doubt Wenger will play with a mixed squad, he has a few injuries to deal with so I would assume it would be no where near the first team out there (also taking into account a couple of players will be away at africa cup of nations). Then factor in the shock results the cup likes to throw up sometimes and you may have a losing last leg.
In saying that, arsenal SHOULD take care of business at home, in the event that they don't, and if you want to middle out a bit, throw a sneaky 10er on Leeds to score more than 1, I'm sure most books would offer that, the price would be around $5, so if there is a shock result you would imagine it would be a high scoring draw as I see arsenal scoring at least 2 against a Leeds side missing their most important defender in Patrick Kisnorbo.
Or you could just ride it out to make it fun, which in any case is probably what I would do.
Just a thought, GL anyway.