Sniper,
You'll definitely benefit from changing to a more advanced last layer method. F2L will make the really big difference, but the last layer can be "big" too, depending upon how much of your solve time is spent in the last layer.
If you're ready to learn a handful of algorithms, I'd suggest learning the 4 Look Last Layer, but learn it first as what amounts to an 8 Look Last Layer. Then, as you add algorithms, those looks will drop away one by one. Let me illustrate:
Looks:
1,2: Orient Edges: This requires two looks in the worst case, using the standard edge flipping algs.
3,4: Orient Corners: If you learn Sune and Anti-Sune (the three corner rotator algs) you can do any of the seven cases with a worst case of applying two of these algs.
5,6: Permute Corners: Again, the worst case scenario of a diagonal corner swap requires two algs to be run; in this case algs A n3 and/or A n4 from this page:
http://cubefreak.net/PLL.html
7,8: Permute edges. The worst case here, of all four edges being out of place requires algs U n1 and/or U n2 from the page above.
Now, to get fewer and fewer looks, you have to add algs. Here's how it breaks down.
1,2: Orient Edges: Learn the alg for flipping all edges at once and you instantly drop one look off. I like OLL 13 from this page:
http://www.cubewhiz.com/oll.html
You can use ANY OLL that starts with ZERO edges solved.
3,4: This is the hardest one. You must learn the all 7 of the corner orientation algs. You should already know two of them, so that's 5 more to learn. Using Macky's numbering system (and page), it's OLLs #21 through #27 on this page:
http://cubefreak.net/OLL.html
Once you learn all 7, you'll drop off a look.
5,6: Permute Corners: Learn one alg for swapping diagonal corners, and you instantly drop off one look. I took the advice on Macky's 4 Look Last Layer page and learned PLL #15 (Y). It swaps diagonal corners and two edges. Learn this and you'll drop off another look:
http://cubefreak.net/twolook.html
7,8: Permute Edges: The two cases that have all 4 edges out of place are #5 Z and #6 H. Learn both of these, and you'll drop off one look.
So, as you progress you get to fewer and fewer looks. When you learn everything I've outlined here, you'll have a 4 Look Last Layer. *Then* to get even faster, you learn the remaining 14 PLLs, which will finally yield a true 3 Look Last Layer. I'm 2 algs from completing that step myself.
As you are learning all of this, you should be solving a lot and working on your F2L and cross. I tried to focus on one thing at a time, and only learned 2 to 5 new algs a week, then let them sink in through time and repetition.
I hope this made some sense.
Brian.