SniperX firstly you should not use the big chain ring with the third biggest rear sprocket if you are using a nine speed. Look at the angle of the chain! Use the small chainring and some of the smaller sprockets such as the 15,16,17 to get the same ratios as 53-21,19 etc..
Pushing bigger gears, takes time and a lot of training, tempo, around 80% MHR and low cadence between 70-80RPM then when you feel fit enough start intervals at lacate threshold between 80 and 90% of MHR depending on fitness say 3mins and 3 sets pushing the big gears say 53 by 19,17 then increase the time up to ten minutes for an interval and ultimately the sets you can do, if you train properly the results you will see are massive!
Bearing in mind this a long term process build a solid base, then tempo then intervals stressing the aerobic then the anerobic system so adaptations can be made.