27.59secs using LBL is quite fast already, you should just progress to Fridrich F2L and there're loads of tutorials on youtube, especially badmephisto's.
Btw you're from Malaysia? Are you in the Malaysian Cube forum?
If you're using Pure LBL, the best you can get is 7 turns... (8 if you count the AUF)
F U2 L F L' U2 F' is the shortest I found.
(It inserts a misoriented edge into the FR position)
What I use for that case is U R U' R' F R' F' R
I don't think it's in alg sheets anywhere, but I think it's the fastest execution if you do an x rotation after U R U' R'
WTF? In your very own recent "Fast cubing with LBL method like Erik" thread we showed you Erik's sub20 video and Dan mentioned his 18.20 average. Are you acting moronic on purpose?