dsusnara,
Take a peek at a few recent threads on others targeting improvement in their times. There are a number of erg-specific training plans targeted at 2K times.
The two that get the most airplay on this site and the UK site forums (which seems a fair bit more active these days) are the Wolverine Plan (WP) (see the thread I just started for pointers to material) and the Pete Plan, a derivative of the WP that requires less reading and planning.
The key to all of this is motivation and commitment. If you have the internal motivation to improve without a targeted event such as a race (erg regatta, team tryout or on the water regatta), great.
If you are like me, you will want to select an event in the next 2-6 months for setting your training goals. It should not be too close in, or you will not really see the impact of your training & it should not be too far out, or the odds are you will lose motivation before reaching your goal.
To state the obvious, if your split is 1:57.9 now and your target pace is 1:52.5, you need to improve by 5.4s/500m. For someone who is already well conditioned, that is a big jump. For someone who has not been executing a structured training program, it may come easily.
As a starter, go to the Pete Plan site and try his beginner's plan for 3-6 weeks. At the end of that period (or maybe each 3 weeks), try a 2K test & see how it goes.
Here is the link:
http://thepeteplan.wordpress.com/beginner-training/
At the end of the initial period, you can make a more informed decision on what plan suits you and how much work you need to do to reach your goal.
Best wishes for success & post what plan you decide on and your progress. There are many people here and on the UK forum who are more than happy to help.
Keep in mind that the advice can sometimes be worth what it cost to give - make your own decisions based on what makes sense to you.
Cheers. Patrick.