Invitations

So this is where we got our invitations.. The best place and cheapest I have seen.. and Trust me I looked!

http://invitationsbydawn.com/index.jsp

For things you want to like create yourself..you can go to 

http://www.orientaltrading.com/party-themes-and-events/wedding-a1-388560+98.fltr

They have awesome things you can buy and customize! Also..check out thingsremembered, thats where I got our champagne glasses and got them engraved there too! you can find them at micheals and joann fabrics i believe as well..but OrienTrade has a lot to choose from and you can gather some ideas too!

Invitations

Thought these invitations look really pretty and have lots of nice designs to choose from..maybe just to get ideas?

http://www.zazzle.com/indian+wedding+invitations

This is one of my favs... http://www.zazzle.com/modern_wedding_invitation-161565807936302515

:) 

Ronald Reagan Building and International Trade Center

Also a really cool place!

http://www.itcdc.com/

Capacity 700, so I think you will be good :)  They have their own catering, but they will work with you to get what you want. Just look at some of the pictures, this place looks amazing!
http://www.itcdc.com/photogallery.php?xmlID=Wedding

FoxChase Manor

Take a look at this place, http://www.weddingwire.com/biz/foxchase-manor-manassas/website/31937ee1055ad53f.html

FoxChase Manor.  Like I said in my email, Erik and I looked at this place, and didn't choose it because it was too big for our party of 180. But I think it would be a wonderful place for you 300-350 guests :)

Also take a look at some of the photos. they have a sweet international weddings album: http://www.weddingwire.com/biz/foxchase-manor-manassas/website/31937ee1055ad53f.html