If you like how the chairs feel and you like the table, keep them. When you get new replacements for the seats, make sure they are solid, like 1/2 plywood, not strand board though. Talk with someone who has done this before. You want a wood which is not too stiff, but you want something sturdy. It would great if you could find solid pine and have the wood; cut, rounded, and sanded. Then, you wouldn't need to put fabric on them. I would take the time to ask a local carpenter if they can make new bottoms out of real wood. If you want to keep them and don't need to rush this job, take your time and get something you won't have to mess with for years. You'll be happier all the way around if you feel a kinship with the set.

Love the idea of classic design juxtaposed with something really organic. Here are a couple of pics of the Eames molded plastic chair with a wood table. Simple, clean. You can get knock-offs for far less if you look and may even be able to score an original if you're willing to really take the time. Of course you can always go to DWR too!

Pic1:Painting I want to hang Pic2:sofa I want to place under the painting

A roof extension, a la Mark VI, makes sense for function, and for attractiveness. Extending the porch and larger roof sounds like an expensive alternative. I suggest keeping the "footprint" of your porch, and spend the money on the porch cover which is part of the roof. What is most important is keeping with the lines of the ranch style roof of the original...not too tall or steep a pitch. In other words, the angle/slope of the addition has to blend with the original roof, something an architect or architectural designer could do for you pretty inexpensively...for getting it right. Also, ask the pros for advice on the size of columns for your addition. I have seen some in my own neighborhood of 1950's versions where some columns are too narrow and look spindly, and some that are too substantial and overwhelm the front of a one-story. Mark VI's pic shows an example that is proportional. Shutters are colonial/traditional in style, but could work as in Mark VI's ideas of the gable with an arched opening, which gives a slight cottage look to the entry without fighting the ranch look. On the less expensive side, some three dimensional foundation plantings would do wonders to 1. encompass the porch, (like adding a frame and a mat to a painting), 2. cozy up your home, (I picture more plantings "wrapping" it with a feeling of being established), 3. camouflage the foundation while tying the house to the lawn and 4. softening the simple lines of the ranch style. The simple version is to think tall/medium/short, evergreens that would stay below window level except maybe a taller one to the right of the windows on the right, offset those plantings with your existing medium height plants in a different "texture" and maybe annuals as the third and front level. Make sure to leave growing room and not plant too close to the foundation. Definitely would soften the look to add a curved sidewalk, sweeping gently from the door out toward the drive...brick pavers would tie in nicely. Altho you don't have the natural treed landscape of K2's first photo, the softness of the curves can demonstrate how that idea can work. Sculpting out the front line of your foundation beds adds dimension and the opportunity to have a focus plant/tree out from the house but in your beds...crape myrtles, Japanese yews, a specimen "tree" that would stay smallish, spring "flowering" or pretty fall colors, appropriate to your climate. All of this would pull your porch into the front lawn as if it all belonged together as had grown organically. If you want a place to sit out front (which you didn't say, but responders seem to want you to make it "homey" in this way) it would be attractive and welcoming to have a seating area to the left of the door and the new sidewalk, perhaps with a plant edging tied to the left foundation bed or stepping stones from new walkway, a little away from the house, a paver patio with bistro table and chairs or adirondack chairs or bench with a 50's flare, with a few potted plants for defining the area. All this would draw the eye from the street to the left seating area, to the walk and plantings on the right, to your new porch as a welcoming entry to the house...not an afterthought, which the awning was.