Replace String what is the best way

[Potato.Head]

Hi to all, I'm working in a application that needs to replace a certain string from a file. I need to create like a dictionary, I'll explain my self.

1. I need to search the string 'class.type='
2. The string can be in the file like:
class.type=var; or class.type =var; or
class.type= var; or class.type = var; or
A.class.type=var; or B.class.type=var; or
You can see than can be with/without spaces, also the string 'var' can be any string(I put var for an example, also sometimes I have a string before the string I'm looking in the example I put A/B.
3. I need to find the index of the 'class.type=' and find the index until certain chars, I'll explain, for example in the following cases, I need to find until '{};'
{A.class.type=var;
}A.class.type=var;
;A.class.type=var;

4. Then I need to find the index of ';' from the string 'class.type='
5. In the end I will have two index.
The result:
Example 1:
Input:
if(a==1)A.class.type=var;
Output:
if(a==1){}
Example 2:
Input:
if(a==1)class.type=var;
Output:
if(a==1){}

I already did this but I think not in a elegant and efficient code, I read that there are regular expressions that can help me, but I never work with them.
I know is a lot of work, but I'll appreciate any suggestions to improve and write a efficient code.
Thanks in advanced:?:

[Tekmaven]

Regular expressions are the way to go. Using them in C# is easy, but developing the actual regular expression is slightly complicated. There are two tools that I've used in the past to help me craft regular expressions, Regulazy and Regulator, both are made by Roy Osherove, and you can download them here: http://weblogs.asp.net/rosherove/pages/tools-and-frameworks-by-roy-osherove.aspx.