Some quality problem with dark picture

[jawt]

Hi, just bought a E510 two weeks ago. I love to take some good quality picture , but im beginner with SLR. My current main problem is that i seen to have noise on DARK picture*i thnik*.. The noise redustion options is enable. i dont use a tripod. My second question is that it worth the cost to buy tripod to get higher quality picture?

let me see these example...

On the first picture, maybe it's hard to see but the dark area on the boat as noise or it,s blurry.

Second one, look tree at the right in dark area.

#1 Metadata

Exposure mode auto
Focal lenght 18 mm
Lens 18-42mm
ISO 100
F 9.0
1/200

#2 metadata

Exposure mode auto
Focal lenght 18 mm
Lens 18-42mm
f 7.1
1/100


Thx to you guys for taking your time to answer to my question.