H1B 5 年, apply GC and 六年之後 H-1B 的延期

My H1B will be expired in 1 year. I applied GC in July, 2007 and was denied due to my salary was lower (68k) than required wage (72K). I have two choice to apply GC:
1) Apply new case through my employer. But my salary is still low (74k) than required wage (78K).
2) One consulting company would apply green card for me. Is it the better way? In this case, do I need ti trnsfer my H1B to consulting company during application? Can I get the eaqual chance to get the GC? Can I get H1B extension by this way?

Is 1 year enough to apply GC and extend H1B?

Many thanks!