using htaccess file to emulate virtual host - regex

Question

I have an app that functions properly on my local wamp server using the virtual host configuration seen below. I recently purchased shared hosting, but unlike my localhost, I dont have access to Apache's httpd-vhost.conf and instead must manipulate the site root's .htaccess file in order to "wire up" my application properly.
The problem is that I do not know how to use the RewriteEngine to write RewriteRules that can emulate (to some degree) this virtual host config:
<VirtualHost *:80>
ServerName sitename
ServerAdmin webmaster#localhost
DocumentRoot "c:/wamp/www/siteroot"
AliasMatch /(.*)\.(js|css|rdf|xml|ico|txt|gif|html|png|jpg|jpeg|json|eot|woff|svg|ttf|pdf)$ "c:/wamp/www/siteroot/app/$1.$2"
AliasMatch /rest/(.*) "c:/wamp/www/siteroot/rest/$1"
AliasMatch /img/(.*) "c:/wamp/www/siteroot/app/img/$1"
AliasMatch /(.*) "c:/wamp/www/siteroot/app/index.php"
ErrorLog "logs/sitename_app_error.log"
LogLevel warn
CustomLog "logs/sitename_app_access.log combined" %a
</VirtualHost>
<VirtualHost *:80>
ServerName admin.sitename
ServerAdmin webmaster#localhost
DocumentRoot "c:/wamp/www/siteroot"
AliasMatch /app/(.*)\.(js|css|rdf|xml|ico|txt|gif|html|png|jpg|jpeg|json|eot|woff|svg|ttf|pdf)$ "c:/wamp/www/siteroot/app/$1.$2"
AliasMatch /i18n/(.*)\.json$ "/wamp/www/siteroot/app/i18n/$1.json"
AliasMatch /(.*)\.(js|css|rdf|xml|ico|txt|gif|html|png|jpg|jpeg|json|eot|woff|svg|ttf|pdf|csv)$ "c:/wamp/www/siteroot/adminApp/$1.$2"
AliasMatch /rest/(.*) "c:/wamp/www/siteroot/rest/$1"
AliasMatch /img/(.*) "c:/wamp/www/siteroot/adminApp/img/$1"
AliasMatch /(.*) "c:/wamp/www/siteroot/adminApp/index.html"
ErrorLog "logs/sitename_app_error.log"
LogLevel warn
CustomLog "logs/sitename_app_access.log combined" %a
</VirtualHost>
<Directory "c:/wamp/www/siteroot">
Options FollowSymLinks
AllowOverride None
</Directory>
<Directory "c:/wamp/www/siteroot/app">
Options Indexes FollowSymLinks MultiViews
AllowOverride All
</Directory>
<Directory "c:/wamp/www/siteroot/adminApp">
AuthName "Login required"
AuthType Basic
AuthUserFile "c:/wamp/www/siteroot/adminApp/.htpasswd"
AuthGroupFile "/dev/null"
Require valid-user
</Directory>
<Directory "c:/wamp/www/siteroot/rest">
Options Indexes FollowSymLinks MultiViews
AllowOverride All
</Directory>
*note that sitename and siteroot aren't the actual names of the site/filepath.
The aliasMatches are what's most important for my site to "work." This is why I think I can get by using the RewriteRules in .htaccess.
Even if you aren't familiar with RewriteRules, if you could tell me what the regular expressions mean, that would be of great help too! Any assistance is appreciated!