softyjain, If the windows need to be replaced I recommend looking at fixed steel to maintain the narrow profile of the windows and small window lites. Using fixed instead of operating will be a cost savings if you don't need to open them. Another option for hanging from the ceiling is a decorative light or chandelier. That way you still have light into your ceiling at night. We offer Renaissance solid bronze windows that don't require any finish or finish maintenance. Architects designers love the rose bronze color, which closely matches copper gutters. http://www.houzz.com/projects/152134/Renaissance-Solid-Bronze-Windows---Doors-by-Progressive-Solutions You may also be interested in this ideabook- http://www.houzz.com/ideabooks/18543834/thumbs/Bronze--Copper---Steel-Window-Ideas

Bamboo roller blinds are an inexpensive fix. They can be cut to fit and have a decorative look.

Fanxing, you could opt for electronically controlled blinds. Half of your challenges could be addressed at the click of a button. Thanks, Nitin Cornerstone Designs Bangalore

Hello, The window looks a little narrow but is placed in a really interesting place . You could go for creating a nice little bay window type here .for this you would need to create a sitting using wooden ply slightly uptil cill level and a foam seat mattress of the size. For dressing the window, roll up curtain could work the best here,I will attach some references.  Further if u wish to decorate it more in Roman style you could opt for a three side frame made around the window opening (On the wall) Shivani Chandra, Architecture Student Alittle