Hi Harish,
for your kind information, a certification in SAP never gurantees a job, its simple because in certification only theory questions are asked, which are totally different when you work for real scenario in sap, if you wants to do any advance level certifications you can do it, but remember it will boost only your resume and will not surve any purpose with your job hunt (may serve if your luck supports you 
).
When it comes to know about advance level in sap abap, i will prefer you to learn basic syntax and semantics in abap (which is necessary). As we have to understand the meaning of below statement when we are newbie to java ( i hope you don't laugh at me, because it was me who learned it 8 yrs. back )
Public static void main { String args[] }
so in abap there are so many things awhich are so common to us and we have to understands its basics, so that we can make use of it whenever we needs to develop abap related stuffs. Webdynpro is another tool where your knowledge of java will be utilised well (Webdynpro is an advance tool of abap).
So if you contacts with the institute you wants to get trained, please ask about the topic and then plaese revert me with all the topics they will cover, then i can make you choose better options, as i don't know what are there , so if i will make any guess , it will not fruitful to you. You can follow me if you wants, then you will able to contact me directly.
When it comes to your role in any organisation, it varies from company to company, a major problem is that in sap world any senior level post requires END-TO-END implementation experience, so i will prefer to talk to your project head or concerned person in your own organisation if he can do something for you, because in outside world, no one will see your experience in java, but will only see how many end to end implementation you have done 
,
so better to get this advantage from your organisation itself, or talk to any senior person in your organisation, they will sure do any fruitful thing for you.
I am always ready to answer your queries, so feel free to revert me.