First, you'd need a good chord book. Kinokuniya(Pardon my spelling) has a good selection. Choose a book that gives you several variations for a single chord.
Then, buy an instructional book preferably with a VCD/DVD demo.
A good instructional book will teach you picking/finger/chording techniques and different types of music styles.
Total, this will set you back somewhere around SGD50 new, else get used books.
For practicing songs, download some chords for songs you like and start strumming along, once you are comfortable, you can improvise.
Also, get a metronome, it will help with your timing a lot.
Once you get better, everything will fall in place.
Remember to start slow and use the metronome, once you are comfortable, go faster slightly.
But always remember to remain comfortable at the pace you are playing.