Help with Query Tuning

Dear all,

I am facing a problem while  creating the index to make the below query run faster. My table  size is near about 1065 MB and 428467 rows.

explain analyze select  count(*)  from page_content where publishing_date like '%2010%' and content_language='en'  and content is not null and isprocessable = 1 and (content like '%Militant%'
OR content like '%jihad%' OR  content like '%Mujahid%'  OR
 content like '%fedayeen%' OR content like '%insurgent%'  OR content like '%terrorist%' OR
  content like '%cadre%'  OR content like '%civilians%' OR content like '%police%' OR content like '%defence%' OR content like '%cops%' OR content like '%crpf%' OR content like '%dsf%' OR content like '%ssb%') AND (content like '%kill%' or content like '%injure%');

Output:

 Aggregate  (cost=107557.78..107557.79 rows=1 width=0) (actual time=18564.631..18564.631 rows=1 loops=1)
   ->  Seq Scan on page_content  (cost=0.00..107466.82 rows=36381 width=0) (actual time=0.146..18529.371 rows=59918 loops=1)
         Filter: ((content IS NOT NULL) AND (publishing_date ~~ '%2010%'::text) AND (content_language = 'en'::bpchar) AND (isprocessable = 1) AND (((content)
::text ~~ '%kill%'::text) OR ((content)::text ~~ '%injure%'::text)) AND (((content)::text ~~ '%Militant%'::text) OR ((content)::text ~~ '%jihad%'::text) OR (
(content)::text ~~ '%Mujahid%'::text) OR ((content)::text ~~ '%fedayeen%'::text) OR ((content)::text ~~ '%insurgent%'::text) OR ((content)::text ~~ '%terrori
st%'::text) OR ((content)::text ~~ '%cadre%'::text) OR ((content)::text ~~ '%civilians%'::text) OR ((content)::text ~~ '%police%'::text) OR ((content)::text
~~ '%defence%'::text) OR ((content)::text ~~ '%cops%'::text) OR ((content)::text ~~ '%crpf%'::text) OR ((content)::text ~~ '%dsf%'::text) OR ((content)::text
 ~~ '%ssb%'::text)))
 Total runtime: 18564.673 ms


Index on that Table :

CREATE INDEX idx_page_id
  ON page_content
  USING btree
  (crawled_page_id);

Index I create :
CREATE INDEX idx_page_id_content
  ON page_content
  USING btree
  (crawled_page_id,content_language,publishing_date,isprocessable);

Index that fail to create:

CREATE INDEX idx_page_id_content1
  ON page_content
  USING btree
  (crawled_page_id,content);

Error :-ERROR:  index row requires 13240 bytes, maximum size is 8191
********** Error **********

ERROR: index row requires 13240 bytes, maximum size is 8191
SQL state: 54000

How to resolve this error
Please give any suggestion to tune the query.

Thanks & best Regards,

Adarsh Sharma