JR pass

A full JR Pass would not be cost effective for your plans, and be a waste of money. The pass is made for long distance travel.
Depending on how much and how far you cover in one day, a Kansai Area Pass might save you some money. One example would be going to see Himeji, which has Japan's finest castle. Osaka has some good sights of course, but the best cities to see are Kyoto and Nara. In Kyoto, the three best sights though are the Kinkakuji Temple, Kiyomizudera Temple, and Fushimi Inari Shrine. Fushimi is the most time consuming; you could spend a couple of hours to over half a day if you want to romp over all the trails. For Nara, don't miss the Todaiji Great Buddha which is marvelous. Uji also has some very nice places as well.

Does the Kansai area pass cover Osaka and Kyoto on those attractions which u mentioned? Do I need to buy in advance?

Thank you.

Hi,
Yes, all the places I mentioned are covered under the Kansai Area Pass. Please see the map in the link I gave above. If you wanted to go beyond that, there is also the Kansai Area Wide Pass which is considerably more expensive, but you can take the bullet train (including the fastest one, the Nozomi) and get from Osaka to Okayama in as little as 45 minutes (and it's 180km away).
Okayama is famous for its castle, plus Korakuen Garden, one of Japan's Top 3, and also the Handayama Garden. If you'd like to get off the beaten trail for a while, the half day hike up to Konpirasan in Kotohira is stunning. Going to Takamatsu is also nice - it has one of Japan's finest gardens also, called Ritsurin.

You can get a tiny discount for buying it online. There is one advantage though - if you buy it in Japan, you can only do it one time only. So if you buy it online, and want to buy another in Japan, you can use 2 passes in Japan (as long as the times don't overlap).

Osaka is best at night, to see Dotonbori, plus the night views from the Umeda Sky Bldg, and Abeno Harukas Bldg are wonderful. Kobe has some good places as well, including its Nankinmachi Chinatown, Arima hot spring, Sorakuen Garden, ropeway, and mountaintop view from Mt. Rokko.

Best of luck.

Toraneko,

You really have been a great help and making it so much easier. Thank you very much.

Cheers