you probably can leave your index.php file alone to serve as your frontpage template and then create a new individual archive template. use rewrite rules to point an address to a certain temmplate.
for a different individual archive template called ‘individual-template.php’-
old
RewriteRule ^archives/([0-9]{4})?/?([0-9]{1,2})?/?([0-9]{1,2})?/?([_0-9a-z-]+)?/?([0-9]+)?/?$ /index.php?year=$1&monthnum=$2&day=$3&name=$4&page=$5 [QSA]
new
RewriteRule ^archives/([0-9]{4})?/?([0-9]{1,2})?/?([0-9]{1,2})?/?([_0-9a-z-]+)?/?([0-9]+)?/?$ /individual-template.php?year=$1&monthnum=$2&day=$3&name=$4&page=$5 [QSA]
for a different category template called ‘category-template.php’-
old
RewriteRule ^archives/category/?(.*) /index.php?category_name=$1 [QSA]
new
RewriteRule ^archives/category/?(.*) /category-template.php?category_name=$1 [QSA]